 |
 |
 |
| pigpio pigpio C I/F pigpiod pigpiod C I/F Python pigs piscope Misc Examples Download FAQ Site Map | pigpio C Interfacepigpio is a C library for the Raspberry which allows control of the GPIO. Featureso hardware timed PWM on any of GPIO 0-31o hardware timed servo pulses on any of GPIO 0-31 o callbacks when any of GPIO 0-31 change state o callbacks at timed intervals o reading/writing all of the GPIO in a bank as one operation o individually setting GPIO modes, reading and writing o notifications when any of GPIO 0-31 change state o the construction of output waveforms with microsecond timing o rudimentary permission control over GPIO o a simple interface to start and stop new threads o I2C, SPI, and serial link wrappers o creating and running scripts GPIOALL GPIO are identified by their Broadcom number.CreditsThe PWM and servo pulses are timed using the DMA and PWM peripherals.This use was inspired by Richard Hirst's servoblaster kernel module. UsageInclude <pigpio.h> in your source files.Assuming your source is in prog.c use the following command to build and run the executable. gcc -Wall -pthread -o prog prog.c -lpigpio -lrtFor examples of usage see the C programs within the pigpio archive file. NotesAll the functions which return an int return < 0 on error.gpioInitialise must be called before all other library functions with the following exceptions: gpioCfg*If the library is not initialised all but the gpioCfg*, gpioVersion, and gpioHardwareRevision functions will return error PI_NOT_INITIALISED. If the library is initialised the gpioCfg* functions will return error PI_INITIALISED. OVERVIEW
FUNCTIONSint gpioInitialise(void)Initialises the library.Returns the pigpio version number if OK, otherwise PI_INIT_FAILED. gpioInitialise must be called before using the other library functions with the following exceptions: gpioCfg*Example if (gpioInitialise() < 0)void gpioTerminate(void)Terminates the library.Returns nothing. Call before program exit. This function resets the used DMA channels, releases memory, and terminates any running threads. Example gpioTerminate();int gpioSetMode(unsigned gpio, unsigned mode)Sets the GPIO mode, typically input or output.gpio: 0-53Returns 0 if OK, otherwise PI_BAD_GPIO or PI_BAD_MODE. Arduino style: pinMode. Example gpioSetMode(17, PI_INPUT); // Set GPIO17 as input.See http://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2835/BCM2835-ARM-Peripherals.pdf page 102 for an overview of the modes. int gpioGetMode(unsigned gpio)Gets the GPIO mode.gpio: 0-53Returns the GPIO mode if OK, otherwise PI_BAD_GPIO. Example if (gpioGetMode(17) != PI_ALT0)int gpioSetPullUpDown(unsigned gpio, unsigned pud)Sets or clears resistor pull ups or downs on the GPIO.gpio: 0-53Returns 0 if OK, otherwise PI_BAD_GPIO or PI_BAD_PUD. Example gpioSetPullUpDown(17, PI_PUD_UP); // Sets a pull-up.int gpioRead(unsigned gpio)Reads the GPIO level, on or off.gpio: 0-53Returns the GPIO level if OK, otherwise PI_BAD_GPIO. Arduino style: digitalRead. Example printf("GPIO24 is level %d", gpioRead(24));int gpioWrite(unsigned gpio, unsigned level)Sets the GPIO level, on or off. gpio: 0-53Returns 0 if OK, otherwise PI_BAD_GPIO or PI_BAD_LEVEL. If PWM or servo pulses are active on the GPIO they are switched off. Arduino style: digitalWrite Example gpioWrite(24, 1); // Set GPIO24 high.int gpioPWM(unsigned user_gpio, unsigned dutycycle)Starts PWM on the GPIO, dutycycle between 0 (off) and range (fully on). Range defaults to 255.user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO or PI_BAD_DUTYCYCLE. Arduino style: analogWrite This and the servo functionality use the DMA and PWM or PCM peripherals to control and schedule the pulse lengths and dutycycles. The gpioSetPWMrange function may be used to change the default range of 255. Example gpioPWM(17, 255); // Sets GPIO17 full on.int gpioGetPWMdutycycle(unsigned user_gpio)Returns the PWM dutycycle setting for the GPIO.user_gpio: 0-31Returns between 0 (off) and range (fully on) if OK, otherwise PI_BAD_USER_GPIO or PI_NOT_PWM_GPIO. For normal PWM the dutycycle will be out of the defined range for the GPIO (see gpioGetPWMrange). If a hardware clock is active on the GPIO the reported dutycycle will be 500000 (500k) out of 1000000 (1M). If hardware PWM is active on the GPIO the reported dutycycle will be out of a 1000000 (1M). Normal PWM range defaults to 255. int gpioSetPWMrange(unsigned user_gpio, unsigned range)Selects the dutycycle range to be used for the GPIO. Subsequent calls to gpioPWM will use a dutycycle between 0 (off) and range (fully on).user_gpio: 0-31Returns the real range for the given GPIO's frequency if OK, otherwise PI_BAD_USER_GPIO or PI_BAD_DUTYRANGE. If PWM is currently active on the GPIO its dutycycle will be scaled to reflect the new range. The real range, the number of steps between fully off and fully on for each frequency, is given in the following table. 25, 50, 100, 125, 200, 250, 400, 500, 625,The real value set by gpioPWM is (dutycycle * real range) / range. Example gpioSetPWMrange(24, 2000); // Now 2000 is fully onint gpioGetPWMrange(unsigned user_gpio)Returns the dutycycle range used for the GPIO if OK, otherwise PI_BAD_USER_GPIO.user_gpio: 0-31If a hardware clock or hardware PWM is active on the GPIO the reported range will be 1000000 (1M). Example r = gpioGetPWMrange(23);int gpioGetPWMrealRange(unsigned user_gpio)Returns the real range used for the GPIO if OK, otherwise PI_BAD_USER_GPIO.user_gpio: 0-31If a hardware clock is active on the GPIO the reported real range will be 1000000 (1M). If hardware PWM is active on the GPIO the reported real range will be approximately 250M divided by the set PWM frequency. Example rr = gpioGetPWMrealRange(17);int gpioSetPWMfrequency(unsigned user_gpio, unsigned frequency)Sets the frequency in hertz to be used for the GPIO.user_gpio: 0-31Returns the numerically closest frequency if OK, otherwise PI_BAD_USER_GPIO. If PWM is currently active on the GPIO it will be switched off and then back on at the new frequency. Each GPIO can be independently set to one of 18 different PWM frequencies. The selectable frequencies depend upon the sample rate which may be 1, 2, 4, 5, 8, or 10 microseconds (default 5). The frequencies for each sample rate are: HertzExample gpioSetPWMfrequency(23, 0); // Set GPIO23 to lowest frequency.int gpioGetPWMfrequency(unsigned user_gpio)Returns the frequency (in hertz) used for the GPIO if OK, otherwise PI_BAD_USER_GPIO.user_gpio: 0-31For normal PWM the frequency will be that defined for the GPIO by gpioSetPWMfrequency. If a hardware clock is active on the GPIO the reported frequency will be that set by gpioHardwareClock. If hardware PWM is active on the GPIO the reported frequency will be that set by gpioHardwarePWM. Example f = gpioGetPWMfrequency(23); // Get frequency used for GPIO23.int gpioServo(unsigned user_gpio, unsigned pulsewidth)Starts servo pulses on the GPIO, 0 (off), 500 (most anti-clockwise) to 2500 (most clockwise). user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO or PI_BAD_PULSEWIDTH. The range supported by servos varies and should probably be determined by experiment. A value of 1500 should always be safe and represents the mid-point of rotation. You can DAMAGE a servo if you command it to move beyond its limits. The following causes an on pulse of 1500 microseconds duration to be transmitted on GPIO 17 at a rate of 50 times per second. This will command a servo connected to GPIO 17 to rotate to its mid-point. Example gpioServo(17, 1000); // Move servo to safe position anti-clockwise.OTHER UPDATE RATES: This function updates servos at 50Hz. If you wish to use a different update frequency you will have to use the PWM functions. PWM Hz 50 100 200 400 500Firstly set the desired PWM frequency using gpioSetPWMfrequency. Then set the PWM range using gpioSetPWMrange to 1E6/frequency. Doing this allows you to use units of microseconds when setting the servo pulsewidth. E.g. If you want to update a servo connected to GPIO25 at 400Hz gpioSetPWMfrequency(25, 400);Thereafter use the PWM command to move the servo, e.g. gpioPWM(25, 1500) will set a 1500 us pulse. int gpioGetServoPulsewidth(unsigned user_gpio)Returns the servo pulsewidth setting for the GPIO.user_gpio: 0-31Returns 0 (off), 500 (most anti-clockwise) to 2500 (most clockwise) if OK, otherwise PI_BAD_USER_GPIO or PI_NOT_SERVO_GPIO. int gpioSetAlertFunc(unsigned user_gpio, gpioAlertFunc_t f)Registers a function to be called (a callback) when the specified GPIO changes state.user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO. One callback may be registered per GPIO. The callback is passed the GPIO, the new level, and the tick. Parameter Value MeaningThe alert may be cancelled by passing NULL as the function. The GPIO are sampled at a rate set when the library is started. If a value isn't specifically set the default of 5 us is used. The number of samples per second is given in the following table. samplesLevel changes shorter than the sample rate may be missed. The thread which calls the alert functions is triggered nominally 1000 times per second. The active alert functions will be called once per level change since the last time the thread was activated. i.e. The active alert functions will get all level changes but there will be a latency. If you want to track the level of more than one GPIO do so by maintaining the state in the callback. Do not use gpioRead. Remember the event that triggered the callback may have happened several milliseconds before and the GPIO may have changed level many times since then. The tick value is the time stamp of the sample in microseconds, see gpioTick for more details. Example void aFunction(int gpio, int level, uint32_t tick)int gpioSetAlertFuncEx(unsigned user_gpio, gpioAlertFuncEx_t f, void *userdata)Registers a function to be called (a callback) when the specified GPIO changes state.user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO. One callback may be registered per GPIO. The callback is passed the GPIO, the new level, the tick, and the userdata pointer. Parameter Value MeaningSee gpioSetAlertFunc for further details. Only one of gpioSetAlertFunc or gpioSetAlertFuncEx can be registered per GPIO. int gpioSetISRFunc(unsigned gpio, unsigned edge, int timeout, gpioISRFunc_t f)Registers a function to be called (a callback) whenever the specified GPIO interrupt occurs. gpio: 0-53Returns 0 if OK, otherwise PI_BAD_GPIO, PI_BAD_EDGE, or PI_BAD_ISR_INIT. One function may be registered per GPIO. The function is passed the GPIO, the current level, and the current tick. The level will be PI_TIMEOUT if the optional interrupt timeout expires. Parameter Value MeaningThe underlying Linux sysfs GPIO interface is used to provide the interrupt services. The first time the function is called, with a non-NULL f, the GPIO is exported, set to be an input, and set to interrupt on the given edge and timeout. Subsequent calls, with a non-NULL f, can vary one or more of the edge, timeout, or function. The ISR may be cancelled by passing a NULL f, in which case the GPIO is unexported. The tick is that read at the time the process was informed of the interrupt. This will be a variable number of microseconds after the interrupt occurred. Typically the latency will be of the order of 50 microseconds. The latency is not guaranteed and will vary with system load. The level is that read at the time the process was informed of the interrupt, or PI_TIMEOUT if the optional interrupt timeout expired. It may not be the same as the expected edge as interrupts happening in rapid succession may be missed by the kernel (i.e. this mechanism can not be used to capture several interrupts only a few microseconds apart). int gpioSetISRFuncEx(unsigned gpio, unsigned edge, int timeout, gpioISRFuncEx_t f, void *userdata)Registers a function to be called (a callback) whenever the specified GPIO interrupt occurs. gpio: 0-53Returns 0 if OK, otherwise PI_BAD_GPIO, PI_BAD_EDGE, or PI_BAD_ISR_INIT. The function is passed the GPIO, the current level, the current tick, and the userdata pointer. Parameter Value MeaningOnly one of gpioSetISRFunc or gpioSetISRFuncEx can be registered per GPIO. See gpioSetISRFunc for further details. int gpioNotifyOpen(void)This function requests a free notification handle.Returns a handle greater than or equal to zero if OK, otherwise PI_NO_HANDLE. A notification is a method for being notified of GPIO state changes via a pipe or socket. Pipe notifications for handle x will be available at the pipe named /dev/pigpiox (where x is the handle number). E.g. if the function returns 15 then the notifications must be read from /dev/pigpio15. Socket notifications are returned to the socket which requested the handle. Example h = gpioNotifyOpen();int gpioNotifyOpenWithSize(int bufSize)This function requests a free notification handle.It differs from gpioNotifyOpen in that the pipe size may be specified, whereas gpioNotifyOpen uses the default pipe size. See gpioNotifyOpen for further details. int gpioNotifyBegin(unsigned handle, uint32_t bits)This function starts notifications on a previously opened handle.handle: >=0, as returned by gpioNotifyOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. The notification sends state changes for each GPIO whose corresponding bit in bits is set. Each notification occupies 12 bytes in the fifo and has the following structure. typedef structseqno: starts at 0 each time the handle is opened and then increments by one for each report. flags: three flags are defined, PI_NTFY_FLAGS_WDOG, PI_NTFY_FLAGS_ALIVE, and PI_NTFY_FLAGS_EVENT. If bit 5 is set (PI_NTFY_FLAGS_WDOG) then bits 0-4 of the flags indicate a GPIO which has had a watchdog timeout. If bit 6 is set (PI_NTFY_FLAGS_ALIVE) this indicates a keep alive signal on the pipe/socket and is sent once a minute in the absence of other notification activity. If bit 7 is set (PI_NTFY_FLAGS_EVENT) then bits 0-4 of the flags indicate an event which has been triggered. tick: the number of microseconds since system boot. It wraps around after 1h12m. level: indicates the level of each GPIO. If bit 1<<x is set then GPIO x is high. Example // Start notifications for GPIO 1, 4, 6, 7, 10.int gpioNotifyPause(unsigned handle)This function pauses notifications on a previously opened handle.handle: >=0, as returned by gpioNotifyOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. Notifications for the handle are suspended until gpioNotifyBegin is called again. Example gpioNotifyPause(h);int gpioNotifyClose(unsigned handle)This function stops notifications on a previously opened handle and releases the handle for reuse.handle: >=0, as returned by gpioNotifyOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. Example gpioNotifyClose(h);int gpioWaveClear(void)This function clears all waveforms and any data added by calls to the gpioWaveAdd* functions.Returns 0 if OK. Example gpioWaveClear();int gpioWaveAddNew(void)This function starts a new empty waveform.You wouldn't normally need to call this function as it is automatically called after a waveform is created with the gpioWaveCreate function. Returns 0 if OK. Example gpioWaveAddNew();int gpioWaveAddGeneric(unsigned numPulses, gpioPulse_t *pulses)This function adds a number of pulses to the current waveform.numPulses: the number of pulsesReturns the new total number of pulses in the current waveform if OK, otherwise PI_TOO_MANY_PULSES. The pulses are interleaved in time order within the existing waveform (if any). Merging allows the waveform to be built in parts, that is the settings for GPIO#1 can be added, and then GPIO#2 etc. If the added waveform is intended to start after or within the existing waveform then the first pulse should consist of a delay. Example // Construct and send a 30 microsecond square wave.int gpioWaveAddSerial(unsigned user_gpio, unsigned baud, unsigned data_bits, unsigned stop_bits, unsigned offset, unsigned numBytes, char *str)This function adds a waveform representing serial data to the existing waveform (if any). The serial data starts offset microseconds from the start of the waveform.user_gpio: 0-31Returns the new total number of pulses in the current waveform if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_WAVE_BAUD, PI_BAD_DATABITS, PI_BAD_STOPBITS, PI_TOO_MANY_CHARS, PI_BAD_SER_OFFSET, or PI_TOO_MANY_PULSES. NOTES: The serial data is formatted as one start bit, data_bits data bits, and stop_bits/2 stop bits. It is legal to add serial data streams with different baud rates to the same waveform. numBytes is the number of bytes of data in str. The bytes required for each character depend upon data_bits. For data_bits 1-8 there will be one byte per character. For data_bits 9-16 there will be two bytes per character. For data_bits 17-32 there will be four bytes per character. Example #define MSG_LEN 8int gpioWaveCreate(void)This function creates a waveform from the data provided by the prior calls to the gpioWaveAdd* functions. Upon success a wave id greater than or equal to 0 is returned, otherwise PI_EMPTY_WAVEFORM, PI_TOO_MANY_CBS, PI_TOO_MANY_OOL, or PI_NO_WAVEFORM_ID.The data provided by the gpioWaveAdd* functions is consumed by this function. As many waveforms may be created as there is space available. The wave id is passed to gpioWaveTxSend to specify the waveform to transmit. Normal usage would be Step 1. gpioWaveClear to clear all waveforms and added data. Step 2. gpioWaveAdd* calls to supply the waveform data. Step 3. gpioWaveCreate to create the waveform and get a unique id Repeat steps 2 and 3 as needed. Step 4. gpioWaveTxSend with the id of the waveform to transmit. A waveform comprises one of more pulses. Each pulse consists of a gpioPulse_t structure. typedef structThe fields specify 1) the GPIO to be switched on at the start of the pulse. 2) the GPIO to be switched off at the start of the pulse. 3) the delay in microseconds before the next pulse. Any or all the fields can be zero. It doesn't make any sense to set all the fields to zero (the pulse will be ignored). When a waveform is started each pulse is executed in order with the specified delay between the pulse and the next. Returns the new waveform id if OK, otherwise PI_EMPTY_WAVEFORM, PI_NO_WAVEFORM_ID, PI_TOO_MANY_CBS, or PI_TOO_MANY_OOL. int gpioWaveCreatePad(int pctCB, int pctBOOL, int pctTOOL)Similar to gpioWaveCreate, this function creates a waveform but pads the consumed resources. Padded waves of equal dimension can be re-cycled efficiently allowing newly created waves to re-use the resources of deleted waves of the same dimension.pctCB: 0-100, the percent of all DMA control blocks to consume.Upon success a wave id greater than or equal to 0 is returned, otherwise PI_EMPTY_WAVEFORM, PI_TOO_MANY_CBS, PI_TOO_MANY_OOL, or PI_NO_WAVEFORM_ID. Waveform data provided by gpioWaveAdd* and rawWaveAdd* functions are consumed by this function. A usage would be the creation of two waves where one is filled while the other is being transmitted. Each wave is assigned 50% of the resources. This buffer structure allows the transmission of infinite wave sequences. Example // get firstWaveChunk, somehowint gpioWaveDelete(unsigned wave_id)This function deletes the waveform with id wave_id.The wave is flagged for deletion. The resources used by the wave will only be reused when either of the following apply. - all waves with higher numbered wave ids have been deleted or have been flagged for deletion. - a new wave is created which uses exactly the same resources as the current wave (see the C source for gpioWaveCreate for details). wave_id: >=0, as returned by gpioWaveCreateWave ids are allocated in order, 0, 1, 2, etc. Returns 0 if OK, otherwise PI_BAD_WAVE_ID. int gpioWaveTxSend(unsigned wave_id, unsigned wave_mode)This function transmits the waveform with id wave_id. The mode determines whether the waveform is sent once or cycles endlessly. The SYNC variants wait for the current waveform to reach the end of a cycle or finish before starting the new waveform.WARNING: bad things may happen if you delete the previous waveform before it has been synced to the new waveform. NOTE: Any hardware PWM started by gpioHardwarePWM will be cancelled. wave_id: >=0, as returned by gpioWaveCreateReturns the number of DMA control blocks in the waveform if OK, otherwise PI_BAD_WAVE_ID, or PI_BAD_WAVE_MODE. int gpioWaveChain(char *buf, unsigned bufSize)This function transmits a chain of waveforms.NOTE: Any hardware PWM started by gpioHardwarePWM will be cancelled. The waves to be transmitted are specified by the contents of buf which contains an ordered list of wave_ids and optional command codes and related data. buf: pointer to the wave_ids and optional command codesReturns 0 if OK, otherwise PI_CHAIN_NESTING, PI_CHAIN_LOOP_CNT, PI_BAD_CHAIN_LOOP, PI_BAD_CHAIN_CMD, PI_CHAIN_COUNTER, PI_BAD_CHAIN_DELAY, PI_CHAIN_TOO_BIG, or PI_BAD_WAVE_ID. Each wave is transmitted in the order specified. A wave may occur multiple times per chain. A blocks of waves may be transmitted multiple times by using the loop commands. The block is bracketed by loop start and end commands. Loops may be nested. Delays between waves may be added with the delay command. The following command codes are supported:
If present Loop Forever must be the last entry in the chain. The code is currently dimensioned to support a chain with roughly 600 entries and 20 loop counters. Example #include <stdio.h>int gpioWaveTxAt(void)This function returns the id of the waveform currently being transmitted.Returns the waveform id or one of the following special values: PI_WAVE_NOT_FOUND (9998) - transmitted wave not found. PI_NO_TX_WAVE (9999) - no wave being transmitted. int gpioWaveTxBusy(void)This function checks to see if a waveform is currently being transmitted.Returns 1 if a waveform is currently being transmitted, otherwise 0. int gpioWaveTxStop(void)This function aborts the transmission of the current waveform.Returns 0 if OK. This function is intended to stop a waveform started in repeat mode. int gpioWaveGetMicros(void)This function returns the length in microseconds of the current waveform.int gpioWaveGetHighMicros(void)This function returns the length in microseconds of the longest waveform created since gpioInitialise was called.int gpioWaveGetMaxMicros(void)This function returns the maximum possible size of a waveform in microseconds.int gpioWaveGetPulses(void)This function returns the length in pulses of the current waveform.int gpioWaveGetHighPulses(void)This function returns the length in pulses of the longest waveform created since gpioInitialise was called.int gpioWaveGetMaxPulses(void)This function returns the maximum possible size of a waveform in pulses.int gpioWaveGetCbs(void)This function returns the length in DMA control blocks of the current waveform.int gpioWaveGetHighCbs(void)This function returns the length in DMA control blocks of the longest waveform created since gpioInitialise was called.int gpioWaveGetMaxCbs(void)This function returns the maximum possible size of a waveform in DMA control blocks.int gpioSerialReadOpen(unsigned user_gpio, unsigned baud, unsigned data_bits)This function opens a GPIO for bit bang reading of serial data.user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_WAVE_BAUD, PI_BAD_DATABITS, or PI_GPIO_IN_USE. The serial data is returned in a cyclic buffer and is read using gpioSerialRead. It is the caller's responsibility to read data from the cyclic buffer in a timely fashion. int gpioSerialReadInvert(unsigned user_gpio, unsigned invert)This function configures the level logic for bit bang serial reads.Use PI_BB_SER_INVERT to invert the serial logic and PI_BB_SER_NORMAL for normal logic. Default is PI_BB_SER_NORMAL. user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_GPIO_IN_USE, PI_NOT_SERIAL_GPIO, or PI_BAD_SER_INVERT. The GPIO must be opened for bit bang reading of serial data using gpioSerialReadOpen prior to calling this function. int gpioSerialRead(unsigned user_gpio, void *buf, size_t bufSize)This function copies up to bufSize bytes of data read from the bit bang serial cyclic buffer to the buffer starting at buf.user_gpio: 0-31, previously opened with gpioSerialReadOpenReturns the number of bytes copied if OK, otherwise PI_BAD_USER_GPIO or PI_NOT_SERIAL_GPIO. The bytes returned for each character depend upon the number of data bits data_bits specified in the gpioSerialReadOpen command. For data_bits 1-8 there will be one byte per character. For data_bits 9-16 there will be two bytes per character. For data_bits 17-32 there will be four bytes per character. int gpioSerialReadClose(unsigned user_gpio)This function closes a GPIO for bit bang reading of serial data.user_gpio: 0-31, previously opened with gpioSerialReadOpenReturns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_SERIAL_GPIO. int i2cOpen(unsigned i2cBus, unsigned i2cAddr, unsigned i2cFlags)This returns a handle for the device at the address on the I2C bus. i2cBus: >=0No flags are currently defined. This parameter should be set to zero. Physically buses 0 and 1 are available on the Pi. Higher numbered buses will be available if a kernel supported bus multiplexor is being used. The GPIO used are given in the following table.
Returns a handle (>=0) if OK, otherwise PI_BAD_I2C_BUS, PI_BAD_I2C_ADDR, PI_BAD_FLAGS, PI_NO_HANDLE, or PI_I2C_OPEN_FAILED. For the SMBus commands the low level transactions are shown at the end of the function description. The following abbreviations are used. S (1 bit) : Start bitint i2cClose(unsigned handle)This closes the I2C device associated with the handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. int i2cWriteQuick(unsigned handle, unsigned bit)This sends a single bit (in the Rd/Wr bit) to the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. Quick command. SMBus 2.0 5.5.1 S Addr bit [A] Pint i2cWriteByte(unsigned handle, unsigned bVal)This sends a single byte to the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. Send byte. SMBus 2.0 5.5.2 S Addr Wr [A] bVal [A] Pint i2cReadByte(unsigned handle)This reads a single byte from the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns the byte read (>=0) if OK, otherwise PI_BAD_HANDLE, or PI_I2C_READ_FAILED. Receive byte. SMBus 2.0 5.5.3 S Addr Rd [A] [Data] NA Pint i2cWriteByteData(unsigned handle, unsigned i2cReg, unsigned bVal)This writes a single byte to the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. Write byte. SMBus 2.0 5.5.4 S Addr Wr [A] i2cReg [A] bVal [A] Pint i2cWriteWordData(unsigned handle, unsigned i2cReg, unsigned wVal)This writes a single 16 bit word to the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. Write word. SMBus 2.0 5.5.4 S Addr Wr [A] i2cReg [A] wValLow [A] wValHigh [A] Pint i2cReadByteData(unsigned handle, unsigned i2cReg)This reads a single byte from the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns the byte read (>=0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. Read byte. SMBus 2.0 5.5.5 S Addr Wr [A] i2cReg [A] S Addr Rd [A] [Data] NA Pint i2cReadWordData(unsigned handle, unsigned i2cReg)This reads a single 16 bit word from the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns the word read (>=0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. Read word. SMBus 2.0 5.5.5 S Addr Wr [A] i2cReg [A] S Addr Rd [A] [DataLow] A [DataHigh] NA Pint i2cProcessCall(unsigned handle, unsigned i2cReg, unsigned wVal)This writes 16 bits of data to the specified register of the device associated with handle and reads 16 bits of data in return.handle: >=0, as returned by a call to i2cOpenReturns the word read (>=0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. Process call. SMBus 2.0 5.5.6 S Addr Wr [A] i2cReg [A] wValLow [A] wValHigh [A]int i2cWriteBlockData(unsigned handle, unsigned i2cReg, char *buf, unsigned count)This writes up to 32 bytes to the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. Block write. SMBus 2.0 5.5.7 S Addr Wr [A] i2cReg [A] count [A]int i2cReadBlockData(unsigned handle, unsigned i2cReg, char *buf)This reads a block of up to 32 bytes from the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenThe amount of returned data is set by the device. Returns the number of bytes read (>=0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. Block read. SMBus 2.0 5.5.7 S Addr Wr [A] i2cReg [A]int i2cBlockProcessCall(unsigned handle, unsigned i2cReg, char *buf, unsigned count)This writes data bytes to the specified register of the device associated with handle and reads a device specified number of bytes of data in return.handle: >=0, as returned by a call to i2cOpenReturns the number of bytes read (>=0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. The SMBus 2.0 documentation states that a minimum of 1 byte may be sent and a minimum of 1 byte may be received. The total number of bytes sent/received must be 32 or less. Block write-block read. SMBus 2.0 5.5.8 S Addr Wr [A] i2cReg [A] count [A] buf0 [A] ... bufn [A]int i2cReadI2CBlockData(unsigned handle, unsigned i2cReg, char *buf, unsigned count)This reads count bytes from the specified register of the device associated with handle . The count may be 1-32.handle: >=0, as returned by a call to i2cOpenReturns the number of bytes read (>0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. S Addr Wr [A] i2cReg [A]int i2cWriteI2CBlockData(unsigned handle, unsigned i2cReg, char *buf, unsigned count)This writes 1 to 32 bytes to the specified register of the device associated with handle.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. S Addr Wr [A] i2cReg [A] buf0 [A] buf1 [A] ... [A] bufn [A] Pint i2cReadDevice(unsigned handle, char *buf, unsigned count)This reads count bytes from the raw device into buf.handle: >=0, as returned by a call to i2cOpenReturns count (>0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_READ_FAILED. S Addr Rd [A] [buf0] A [buf1] A ... A [bufn] NA Pint i2cWriteDevice(unsigned handle, char *buf, unsigned count)This writes count bytes from buf to the raw device.handle: >=0, as returned by a call to i2cOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_I2C_WRITE_FAILED. S Addr Wr [A] buf0 [A] buf1 [A] ... [A] bufn [A] Pvoid i2cSwitchCombined(int setting)This sets the I2C (i2c-bcm2708) module "use combined transactions" parameter on or off.setting: 0 to set the parameter off, non-zero to set it onNOTE: when the flag is on a write followed by a read to the same slave address will use a repeated start (rather than a stop/start). int i2cSegments(unsigned handle, pi_i2c_msg_t *segs, unsigned numSegs)This function executes multiple I2C segments in one transaction by calling the I2C_RDWR ioctl. handle: >=0, as returned by a call to i2cOpenReturns the number of segments if OK, otherwise PI_BAD_I2C_SEG. int i2cZip(unsigned handle, char *inBuf, unsigned inLen, char *outBuf, unsigned outLen)This function executes a sequence of I2C operations. The operations to be performed are specified by the contents of inBuf which contains the concatenated command codes and associated data.handle: >=0, as returned by a call to i2cOpenReturns >= 0 if OK (the number of bytes read), otherwise PI_BAD_HANDLE, PI_BAD_POINTER, PI_BAD_I2C_CMD, PI_BAD_I2C_RLEN. PI_BAD_I2C_WLEN, or PI_BAD_I2C_SEG. The following command codes are supported:
The address, read, and write commands take a parameter P. Normally P is one byte (0-255). If the command is preceded by the Escape command then P is two bytes (0-65535, least significant byte first). The address defaults to that associated with the handle. The flags default to 0. The address and flags maintain their previous value until updated. The returned I2C data is stored in consecutive locations of outBuf. Example Set address 0x53, write 0x32, read 6 bytesint bbI2COpen(unsigned SDA, unsigned SCL, unsigned baud)This function selects a pair of GPIO for bit banging I2C at a specified baud rate.Bit banging I2C allows for certain operations which are not possible with the standard I2C driver. o baud rates as low as 50 o repeated starts o clock stretching o I2C on any pair of spare GPIO SDA: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_I2C_BAUD, or PI_GPIO_IN_USE. NOTE: The GPIO used for SDA and SCL must have pull-ups to 3V3 connected. As a guide the hardware pull-ups on pins 3 and 5 are 1k8 in value. int bbI2CClose(unsigned SDA)This function stops bit banging I2C on a pair of GPIO previously opened with bbI2COpen.SDA: 0-31, the SDA GPIO used in a prior call to bbI2COpenReturns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_I2C_GPIO. int bbI2CZip(unsigned SDA, char *inBuf, unsigned inLen, char *outBuf, unsigned outLen)This function executes a sequence of bit banged I2C operations. The operations to be performed are specified by the contents of inBuf which contains the concatenated command codes and associated data. SDA: 0-31 (as used in a prior call to bbI2COpen)Returns >= 0 if OK (the number of bytes read), otherwise PI_BAD_USER_GPIO, PI_NOT_I2C_GPIO, PI_BAD_POINTER, PI_BAD_I2C_CMD, PI_BAD_I2C_RLEN, PI_BAD_I2C_WLEN, PI_I2C_READ_FAILED, or PI_I2C_WRITE_FAILED. The following command codes are supported:
The address, read, and write commands take a parameter P. Normally P is one byte (0-255). If the command is preceded by the Escape command then P is two bytes (0-65535, least significant byte first). The address and flags default to 0. The address and flags maintain their previous value until updated. No flags are currently defined. The returned I2C data is stored in consecutive locations of outBuf. Example Set address 0x53int bscXfer(bsc_xfer_t *bsc_xfer)This function provides a low-level interface to the SPI/I2C Slave peripheral on the BCM chip.This peripheral allows the Pi to act as a hardware slave device on an I2C or SPI bus. This is not a bit bang version and as such is OS timing independent. The bus timing is handled directly by the chip. The output process is simple. You simply append data to the FIFO buffer on the chip. This works like a queue, you add data to the queue and the master removes it. I can't get SPI to work properly. I tried with a control word of 0x303 and swapped MISO and MOSI. The function sets the BSC mode, writes any data in the transmit buffer to the BSC transmit FIFO, and copies any data in the BSC receive FIFO to the receive buffer. bsc_xfer:= a structure defining the transferTo start a transfer set control (see below), copy the bytes to be added to the transmit FIFO (if any) to txBuf and set txCnt to the number of copied bytes. Upon return rxCnt will be set to the number of received bytes placed in rxBuf. Note that the control word sets the BSC mode. The BSC will stay in that mode until a different control word is sent. GPIO used for models other than those based on the BCM2711.
GPIO used for models based on the BCM2711 (e.g. the Pi4B).
When a zero control word is received the used GPIO will be reset to INPUT mode. The returned function value is the status of the transfer (see below). If there was an error the status will be less than zero (and will contain the error code). The most significant word of the returned status contains the number of bytes actually copied from txBuf to the BSC transmit FIFO (may be less than requested if the FIFO already contained untransmitted data). control consists of the following bits. 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0Bits 0-13 are copied unchanged to the BSC CR register. See pages 163-165 of the Broadcom peripherals document for full details.
The returned status has the following format 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0Bits 0-15 are copied unchanged from the BSC FR register. See pages 165-166 of the Broadcom peripherals document for full details.
The following example shows how to configure the BSC peripheral as an I2C slave with address 0x13 and send four bytes. Example bsc_xfer_t xfer;int bbSPIOpen(unsigned CS, unsigned MISO, unsigned MOSI, unsigned SCLK, unsigned baud, unsigned spiFlags)This function selects a set of GPIO for bit banging SPI with a specified baud rate and mode. CS: 0-31spiFlags consists of the least significant 22 bits. 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0mm defines the SPI mode, defaults to 0 Mode CPOL CPHAp is 0 if CS is active low (default) and 1 for active high. T is 1 if the least significant bit is transmitted on MOSI first, the default (0) shifts the most significant bit out first. R is 1 if the least significant bit is received on MISO first, the default (0) receives the most significant bit first. The other bits in flags should be set to zero. Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_SPI_BAUD, or PI_GPIO_IN_USE. If more than one device is connected to the SPI bus (defined by SCLK, MOSI, and MISO) each must have its own CS. Example bbSPIOpen(10, MISO, MOSI, SCLK, 10000, 0); // device 1int bbSPIClose(unsigned CS)This function stops bit banging SPI on a set of GPIO opened with bbSPIOpen.CS: 0-31, the CS GPIO used in a prior call to bbSPIOpenReturns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_SPI_GPIO. int bbSPIXfer(unsigned CS, char *inBuf, char *outBuf, unsigned count)This function executes a bit banged SPI transfer. CS: 0-31 (as used in a prior call to bbSPIOpen)Returns >= 0 if OK (the number of bytes read), otherwise PI_BAD_USER_GPIO, PI_NOT_SPI_GPIO or PI_BAD_POINTER. Example // gcc -Wall -pthread -o bbSPIx_test bbSPIx_test.c -lpigpioint spiOpen(unsigned spiChan, unsigned baud, unsigned spiFlags)This function returns a handle for the SPI device on the channel. Data will be transferred at baud bits per second. The flags may be used to modify the default behaviour of 4-wire operation, mode 0, active low chip select.The Pi has two SPI peripherals: main and auxiliary. The main SPI has two chip selects (channels), the auxiliary has three. The auxiliary SPI is available on all models but the A and B. The GPIO used are given in the following table.
spiChan: 0-1 (0-2 for the auxiliary SPI)Returns a handle (>=0) if OK, otherwise PI_BAD_SPI_CHANNEL, PI_BAD_SPI_SPEED, PI_BAD_FLAGS, PI_NO_AUX_SPI, or PI_SPI_OPEN_FAILED. spiFlags consists of the least significant 22 bits. 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0mm defines the SPI mode. Warning: modes 1 and 3 do not appear to work on the auxiliary SPI. Mode POL PHApx is 0 if CEx is active low (default) and 1 for active high. ux is 0 if the CEx GPIO is reserved for SPI (default) and 1 otherwise. A is 0 for the main SPI, 1 for the auxiliary SPI. W is 0 if the device is not 3-wire, 1 if the device is 3-wire. Main SPI only. nnnn defines the number of bytes (0-15) to write before switching the MOSI line to MISO to read data. This field is ignored if W is not set. Main SPI only. T is 1 if the least significant bit is transmitted on MOSI first, the default (0) shifts the most significant bit out first. Auxiliary SPI only. R is 1 if the least significant bit is received on MISO first, the default (0) receives the most significant bit first. Auxiliary SPI only. bbbbbb defines the word size in bits (0-32). The default (0) sets 8 bits per word. Auxiliary SPI only. The spiRead, spiWrite, and spiXfer functions transfer data packed into 1, 2, or 4 bytes according to the word size in bits. For bits 1-8 there will be one byte per word. For bits 9-16 there will be two bytes per word. For bits 17-32 there will be four bytes per word. Multi-byte transfers are made in least significant byte first order. E.g. to transfer 32 11-bit words buf should contain 64 bytes and count should be 64. E.g. to transfer the 14 bit value 0x1ABC send the bytes 0xBC followed by 0x1A. The other bits in flags should be set to zero. int spiClose(unsigned handle)This functions closes the SPI device identified by the handle.handle: >=0, as returned by a call to spiOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. int spiRead(unsigned handle, char *buf, unsigned count)This function reads count bytes of data from the SPI device associated with the handle.handle: >=0, as returned by a call to spiOpenReturns the number of bytes transferred if OK, otherwise PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or PI_SPI_XFER_FAILED. int spiWrite(unsigned handle, char *buf, unsigned count)This function writes count bytes of data from buf to the SPI device associated with the handle.handle: >=0, as returned by a call to spiOpenReturns the number of bytes transferred if OK, otherwise PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or PI_SPI_XFER_FAILED. int spiXfer(unsigned handle, char *txBuf, char *rxBuf, unsigned count)This function transfers count bytes of data from txBuf to the SPI device associated with the handle. Simultaneously count bytes of data are read from the device and placed in rxBuf.handle: >=0, as returned by a call to spiOpenReturns the number of bytes transferred if OK, otherwise PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or PI_SPI_XFER_FAILED. int serOpen(char *sertty, unsigned baud, unsigned serFlags)This function opens a serial device at a specified baud rate and with specified flags. The device name must start with /dev/tty or /dev/serial. sertty: the serial device to openReturns a handle (>=0) if OK, otherwise PI_NO_HANDLE, or PI_SER_OPEN_FAILED. The baud rate must be one of 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, 115200, or 230400. No flags are currently defined. This parameter should be set to zero. int serClose(unsigned handle)This function closes the serial device associated with handle.handle: >=0, as returned by a call to serOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. int serWriteByte(unsigned handle, unsigned bVal)This function writes bVal to the serial port associated with handle.handle: >=0, as returned by a call to serOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_SER_WRITE_FAILED. int serReadByte(unsigned handle)This function reads a byte from the serial port associated with handle.handle: >=0, as returned by a call to serOpenReturns the read byte (>=0) if OK, otherwise PI_BAD_HANDLE, PI_SER_READ_NO_DATA, or PI_SER_READ_FAILED. If no data is ready PI_SER_READ_NO_DATA is returned. int serWrite(unsigned handle, char *buf, unsigned count)This function writes count bytes from buf to the the serial port associated with handle.handle: >=0, as returned by a call to serOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_SER_WRITE_FAILED. int serRead(unsigned handle, char *buf, unsigned count)This function reads up count bytes from the the serial port associated with handle and writes them to buf.handle: >=0, as returned by a call to serOpenReturns the number of bytes read (>0=) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or PI_SER_READ_NO_DATA. If no data is ready zero is returned. int serDataAvailable(unsigned handle)This function returns the number of bytes available to be read from the device associated with handle.handle: >=0, as returned by a call to serOpenReturns the number of bytes of data available (>=0) if OK, otherwise PI_BAD_HANDLE. int gpioTrigger(unsigned user_gpio, unsigned pulseLen, unsigned level)This function sends a trigger pulse to a GPIO. The GPIO is set to level for pulseLen microseconds and then reset to not level.user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_LEVEL, or PI_BAD_PULSELEN. int gpioSetWatchdog(unsigned user_gpio, unsigned timeout)Sets a watchdog for a GPIO.user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO or PI_BAD_WDOG_TIMEOUT. The watchdog is nominally in milliseconds. One watchdog may be registered per GPIO. The watchdog may be cancelled by setting timeout to 0. Until cancelled a timeout will be reported every timeout milliseconds after the last GPIO activity. In particular: 1) any registered alert function for the GPIO will be called with the level set to PI_TIMEOUT. 2) any notification for the GPIO will have a report written to the fifo with the flags set to indicate a watchdog timeout. Example void aFunction(int gpio, int level, uint32_t tick)int gpioNoiseFilter(unsigned user_gpio, unsigned steady, unsigned active)Sets a noise filter on a GPIO.Level changes on the GPIO are ignored until a level which has been stable for steady microseconds is detected. Level changes on the GPIO are then reported for active microseconds after which the process repeats. user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_BAD_FILTER. This filter affects the GPIO samples returned to callbacks set up with gpioSetAlertFunc, gpioSetAlertFuncEx, gpioSetGetSamplesFunc, and gpioSetGetSamplesFuncEx. It does not affect interrupts set up with gpioSetISRFunc, gpioSetISRFuncEx, or levels read by gpioRead, gpioRead_Bits_0_31, or gpioRead_Bits_32_53. Level changes before and after the active period may be reported. Your software must be designed to cope with such reports. int gpioGlitchFilter(unsigned user_gpio, unsigned steady)Sets a glitch filter on a GPIO.Level changes on the GPIO are not reported unless the level has been stable for at least steady microseconds. The level is then reported. Level changes of less than steady microseconds are ignored. user_gpio: 0-31Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_BAD_FILTER. This filter affects the GPIO samples returned to callbacks set up with gpioSetAlertFunc, gpioSetAlertFuncEx, gpioSetGetSamplesFunc, and gpioSetGetSamplesFuncEx. It does not affect interrupts set up with gpioSetISRFunc, gpioSetISRFuncEx, or levels read by gpioRead, gpioRead_Bits_0_31, or gpioRead_Bits_32_53. Each (stable) edge will be timestamped steady microseconds after it was first detected. int gpioSetGetSamplesFunc(gpioGetSamplesFunc_t f, uint32_t bits)Registers a function to be called (a callback) every millisecond with the latest GPIO samples. f: the function to callReturns 0 if OK. The function is passed a pointer to the samples (an array of gpioSample_t), and the number of samples. Only one function can be registered. The callback may be cancelled by passing NULL as the function. The samples returned will be the union of bits, plus any active alerts, plus any active notifications. e.g. if there are alerts for GPIO 7, 8, and 9, notifications for GPIO 8, 10, 23, 24, and bits is (1<<23)|(1<<17) then samples for GPIO 7, 8, 9, 10, 17, 23, and 24 will be reported. int gpioSetGetSamplesFuncEx(gpioGetSamplesFuncEx_t f, uint32_t bits, void *userdata)Registers a function to be called (a callback) every millisecond with the latest GPIO samples. f: the function to callReturns 0 if OK. The function is passed a pointer to the samples (an array of gpioSample_t), the number of samples, and the userdata pointer. Only one of gpioGetSamplesFunc or gpioGetSamplesFuncEx can be registered. See gpioSetGetSamplesFunc for further details. int gpioSetTimerFunc(unsigned timer, unsigned millis, gpioTimerFunc_t f)Registers a function to be called (a callback) every millis milliseconds. timer: 0-9Returns 0 if OK, otherwise PI_BAD_TIMER, PI_BAD_MS, or PI_TIMER_FAILED. 10 timers are supported numbered 0 to 9. One function may be registered per timer. The timer may be cancelled by passing NULL as the function. Example void bFunction(void)int gpioSetTimerFuncEx(unsigned timer, unsigned millis, gpioTimerFuncEx_t f, void *userdata)Registers a function to be called (a callback) every millis milliseconds. timer: 0-9.Returns 0 if OK, otherwise PI_BAD_TIMER, PI_BAD_MS, or PI_TIMER_FAILED. The function is passed the userdata pointer. Only one of gpioSetTimerFunc or gpioSetTimerFuncEx can be registered per timer. See gpioSetTimerFunc for further details. pthread_t *gpioStartThread(gpioThreadFunc_t f, void *userdata)Starts a new thread of execution with f as the main routine. f: the main function for the new threadReturns a pointer to pthread_t if OK, otherwise NULL. The function is passed the single argument arg. The thread can be cancelled by passing the pointer to pthread_t to gpioStopThread. Example #include <stdio.h>void gpioStopThread(pthread_t *pth)Cancels the thread pointed at by pth.pth: a thread pointer returned by gpioStartThreadNo value is returned. The thread to be stopped should have been started with gpioStartThread. int gpioStoreScript(char *script)This function stores a null terminated script for later execution.See http://abyz.me.uk/rpi/pigpio/pigs.html#Scripts for details. script: the text of the scriptThe function returns a script id if the script is valid, otherwise PI_BAD_SCRIPT. int gpioRunScript(unsigned script_id, unsigned numPar, uint32_t *param)This function runs a stored script.script_id: >=0, as returned by gpioStoreScriptThe function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID, or PI_TOO_MANY_PARAM. param is an array of up to 10 parameters which may be referenced in the script as p0 to p9. int gpioRunScript(unsigned script_id, unsigned numPar, uint32_t *param)This function runs a stored script.script_id: >=0, as returned by gpioStoreScriptThe function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID, or PI_TOO_MANY_PARAM. param is an array of up to 10 parameters which may be referenced in the script as p0 to p9. int gpioUpdateScript(unsigned script_id, unsigned numPar, uint32_t *param)This function sets the parameters of a script. The script may or may not be running. The first numPar parameters of the script are overwritten with the new values.script_id: >=0, as returned by gpioStoreScriptThe function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID, or PI_TOO_MANY_PARAM. param is an array of up to 10 parameters which may be referenced in the script as p0 to p9. int gpioScriptStatus(unsigned script_id, uint32_t *param)This function returns the run status of a stored script as well as the current values of parameters 0 to 9.script_id: >=0, as returned by gpioStoreScriptThe function returns greater than or equal to 0 if OK, otherwise PI_BAD_SCRIPT_ID. The run status may be PI_SCRIPT_INITINGThe current value of script parameters 0 to 9 are returned in param. int gpioStopScript(unsigned script_id)This function stops a running script.script_id: >=0, as returned by gpioStoreScriptThe function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID. int gpioDeleteScript(unsigned script_id)This function deletes a stored script.script_id: >=0, as returned by gpioStoreScriptThe function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID. int gpioSetSignalFunc(unsigned signum, gpioSignalFunc_t f)Registers a function to be called (a callback) when a signal occurs.signum: 0-63Returns 0 if OK, otherwise PI_BAD_SIGNUM. The function is passed the signal number. One function may be registered per signal. The callback may be cancelled by passing NULL. By default all signals are treated as fatal and cause the library to call gpioTerminate and then exit. int gpioSetSignalFuncEx(unsigned signum, gpioSignalFuncEx_t f, void *userdata)Registers a function to be called (a callback) when a signal occurs. signum: 0-63Returns 0 if OK, otherwise PI_BAD_SIGNUM. The function is passed the signal number and the userdata pointer. Only one of gpioSetSignalFunc or gpioSetSignalFuncEx can be registered per signal. See gpioSetSignalFunc for further details. uint32_t gpioRead_Bits_0_31(void)Returns the current level of GPIO 0-31.uint32_t gpioRead_Bits_32_53(void)Returns the current level of GPIO 32-53.int gpioWrite_Bits_0_31_Clear(uint32_t bits)Clears GPIO 0-31 if the corresponding bit in bits is set.bits: a bit mask of GPIO to clearReturns 0 if OK. Example // To clear (set to 0) GPIO 4, 7, and 15int gpioWrite_Bits_32_53_Clear(uint32_t bits)Clears GPIO 32-53 if the corresponding bit (0-21) in bits is set.bits: a bit mask of GPIO to clearReturns 0 if OK. int gpioWrite_Bits_0_31_Set(uint32_t bits)Sets GPIO 0-31 if the corresponding bit in bits is set.bits: a bit mask of GPIO to setReturns 0 if OK. int gpioWrite_Bits_32_53_Set(uint32_t bits)Sets GPIO 32-53 if the corresponding bit (0-21) in bits is set.bits: a bit mask of GPIO to setReturns 0 if OK. Example // To set (set to 1) GPIO 32, 40, and 53int gpioHardwareClock(unsigned gpio, unsigned clkfreq)Starts a hardware clock on a GPIO at the specified frequency. Frequencies above 30MHz are unlikely to work. gpio: see descriptionReturns 0 if OK, otherwise PI_BAD_GPIO, PI_NOT_HCLK_GPIO, PI_BAD_HCLK_FREQ,or PI_BAD_HCLK_PASS. The same clock is available on multiple GPIO. The latest frequency setting will be used by all GPIO which share a clock. The GPIO must be one of the following. 4 clock 0 All modelsAccess to clock 1 is protected by a password as its use will likely crash the Pi. The password is given by or'ing 0x5A000000 with the GPIO number. int gpioHardwarePWM(unsigned gpio, unsigned PWMfreq, unsigned PWMduty)Starts hardware PWM on a GPIO at the specified frequency and dutycycle. Frequencies above 30MHz are unlikely to work.NOTE: Any waveform started by gpioWaveTxSend, or gpioWaveChain will be cancelled. This function is only valid if the pigpio main clock is PCM. The main clock defaults to PCM but may be overridden by a call to gpioCfgClock. gpio: see descriptionReturns 0 if OK, otherwise PI_BAD_GPIO, PI_NOT_HPWM_GPIO, PI_BAD_HPWM_DUTY, PI_BAD_HPWM_FREQ, or PI_HPWM_ILLEGAL. The same PWM channel is available on multiple GPIO. The latest frequency and dutycycle setting will be used by all GPIO which share a PWM channel. The GPIO must be one of the following. 12 PWM channel 0 All models but A and BThe actual number of steps beween off and fully on is the integral part of 250M/PWMfreq (375M/PWMfreq for the BCM2711). The actual frequency set is 250M/steps (375M/steps for the BCM2711). There will only be a million steps for a PWMfreq of 250 (375 for the BCM2711). Lower frequencies will have more steps and higher frequencies will have fewer steps. PWMduty is automatically scaled to take this into account. int gpioTime(unsigned timetype, int *seconds, int *micros)Updates the seconds and micros variables with the current time.timetype: 0 (relative), 1 (absolute)Returns 0 if OK, otherwise PI_BAD_TIMETYPE. If timetype is PI_TIME_ABSOLUTE updates seconds and micros with the number of seconds and microseconds since the epoch (1st January 1970). If timetype is PI_TIME_RELATIVE updates seconds and micros with the number of seconds and microseconds since the library was initialised. Example int secs, mics;int gpioSleep(unsigned timetype, int seconds, int micros)Sleeps for the number of seconds and microseconds specified by seconds and micros.timetype: 0 (relative), 1 (absolute)Returns 0 if OK, otherwise PI_BAD_TIMETYPE, PI_BAD_SECONDS, or PI_BAD_MICROS. If timetype is PI_TIME_ABSOLUTE the sleep ends when the number of seconds and microseconds since the epoch (1st January 1970) has elapsed. System clock changes are taken into account. If timetype is PI_TIME_RELATIVE the sleep is for the specified number of seconds and microseconds. System clock changes do not effect the sleep length. For short delays (say, 50 microseonds or less) use gpioDelay. Example gpioSleep(PI_TIME_RELATIVE, 2, 500000); // sleep for 2.5 secondsuint32_t gpioDelay(uint32_t micros)Delays for at least the number of microseconds specified by micros.micros: the number of microseconds to sleepReturns the actual length of the delay in microseconds. Delays of 100 microseconds or less use busy waits. uint32_t gpioTick(void)Returns the current system tick.Tick is the number of microseconds since system boot. As tick is an unsigned 32 bit quantity it wraps around after 2^32 microseconds, which is approximately 1 hour 12 minutes. You don't need to worry about the wrap around as long as you take a tick (uint32_t) from another tick, i.e. the following code will always provide the correct difference. Example uint32_t startTick, endTick;unsigned gpioHardwareRevision(void)Returns the hardware revision.If the hardware revision can not be found or is not a valid hexadecimal number the function returns 0. The hardware revision is the last few characters on the Revision line of /proc/cpuinfo. The revision number can be used to determine the assignment of GPIO to pins (see gpio). There are at least three types of board. Type 1 boards have hardware revision numbers of 2 and 3. Type 2 boards have hardware revision numbers of 4, 5, 6, and 15. Type 3 boards have hardware revision numbers of 16 or greater. for "Revision : 0002" the function returns 2. for "Revision : 000f" the function returns 15. for "Revision : 000g" the function returns 0. unsigned gpioVersion(void)Returns the pigpio version.int gpioGetPad(unsigned pad)This function returns the pad drive strength in mA.pad: 0-2, the pad to getReturns the pad drive strength if OK, otherwise PI_BAD_PAD.
Example strength = gpioGetPad(1); // get pad 1 strengthint gpioSetPad(unsigned pad, unsigned padStrength)This function sets the pad drive strength in mA. pad: 0-2, the pad to setReturns 0 if OK, otherwise PI_BAD_PAD, or PI_BAD_STRENGTH.
Example gpioSetPad(0, 16); // set pad 0 strength to 16 mAint eventMonitor(unsigned handle, uint32_t bits)This function selects the events to be reported on a previously opened handle.handle: >=0, as returned by gpioNotifyOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. A report is sent each time an event is triggered providing the corresponding bit in bits is set. See gpioNotifyBegin for the notification format. Example // Start reporting events 3, 6, and 7.int eventSetFunc(unsigned event, eventFunc_t f)Registers a function to be called (a callback) when the specified event occurs.event: 0-31Returns 0 if OK, otherwise PI_BAD_EVENT_ID. One function may be registered per event. The function is passed the event, and the tick. The callback may be cancelled by passing NULL as the function. int eventSetFuncEx(unsigned event, eventFuncEx_t f, void *userdata)Registers a function to be called (a callback) when the specified event occurs. event: 0-31Returns 0 if OK, otherwise PI_BAD_EVENT_ID. One function may be registered per event. The function is passed the event, the tick, and the ueserdata pointer. The callback may be cancelled by passing NULL as the function. Only one of eventSetFunc or eventSetFuncEx can be registered per event. int eventTrigger(unsigned event)This function signals the occurrence of an event.event: 0-31, the eventReturns 0 if OK, otherwise PI_BAD_EVENT_ID. An event is a signal used to inform one or more consumers to start an action. Each consumer which has registered an interest in the event (e.g. by calling eventSetFunc) will be informed by a callback. One event, PI_EVENT_BSC (31) is predefined. This event is auto generated on BSC slave activity. The meaning of other events is arbitrary. Note that other than its id and its tick there is no data associated with an event. int shell(char *scriptName, char *scriptString)This function uses the system call to execute a shell script with the given string as its parameter. scriptName: the name of the script, only alphanumeric characters,The exit status of the system call is returned if OK, otherwise PI_BAD_SHELL_STATUS. scriptName must exist in /opt/pigpio/cgi and must be executable. The returned exit status is normally 256 times that set by the shell script exit function. If the script can't be found 32512 will be returned. The following table gives some example returned statuses.
Example // pass two parameters, hello and worldint fileOpen(char *file, unsigned mode)This function returns a handle to a file opened in a specified mode.file: the file to openReturns a handle (>=0) if OK, otherwise PI_NO_HANDLE, PI_NO_FILE_ACCESS, PI_BAD_FILE_MODE, PI_FILE_OPEN_FAILED, or PI_FILE_IS_A_DIR. File A file may only be opened if permission is granted by an entry in /opt/pigpio/access. This is intended to allow remote access to files in a more or less controlled manner. Each entry in /opt/pigpio/access takes the form of a file path which may contain wildcards followed by a single letter permission. The permission may be R for read, W for write, U for read/write, and N for no access. Where more than one entry matches a file the most specific rule applies. If no entry matches a file then access is denied. Suppose /opt/pigpio/access contains the following entries /home/* nFiles may be written in directory dir_1 with the exception of file.txt. Files may be read in directory dir_2. Files may be read and written in directory dir_3. If a directory allows read, write, or read/write access then files may be created in that directory. In an attempt to prevent risky permissions the following paths are ignored in /opt/pigpio/access. a path containing ..Mode The mode may have the following values.
The following values may be or'd into the mode.
Newly created files are owned by root with permissions owner read and write. Example #include <stdio.h>int fileClose(unsigned handle)This function closes the file associated with handle.handle: >=0, as returned by a call to fileOpenReturns 0 if OK, otherwise PI_BAD_HANDLE. Example fileClose(h);int fileWrite(unsigned handle, char *buf, unsigned count)This function writes count bytes from buf to the the file associated with handle.handle: >=0, as returned by a call to fileOpenReturns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, PI_FILE_NOT_WOPEN, or PI_BAD_FILE_WRITE. Example status = fileWrite(h, buf, count);int fileRead(unsigned handle, char *buf, unsigned count)This function reads up to count bytes from the the file associated with handle and writes them to buf.handle: >=0, as returned by a call to fileOpenReturns the number of bytes read (>=0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, PI_FILE_NOT_ROPEN, or PI_BAD_FILE_WRITE. Example if (fileRead(h, buf, sizeof(buf)) > 0)int fileSeek(unsigned handle, int32_t seekOffset, int seekFrom)This function seeks to a position within the file associated with handle. handle: >=0, as returned by a call to fileOpenReturns the new byte position within the file (>=0) if OK, otherwise PI_BAD_HANDLE, or PI_BAD_FILE_SEEK. Example fileSeek(0, 20, PI_FROM_START); // Seek to start plus 20int fileList(char *fpat, char *buf, unsigned count)This function returns a list of files which match a pattern. The pattern may contain wildcards. fpat: file pattern to matchReturns the number of returned bytes if OK, otherwise PI_NO_FILE_ACCESS, or PI_NO_FILE_MATCH. The pattern must match an entry in /opt/pigpio/access. The pattern may contain wildcards. See fileOpen. NOTE The returned value is not the number of files, it is the number of bytes in the buffer. The file names are separated by newline characters. Example #include <stdio.h>int gpioCfgBufferSize(unsigned cfgMillis)Configures pigpio to buffer cfgMillis milliseconds of GPIO samples.This function is only effective if called before gpioInitialise. cfgMillis: 100-10000The default setting is 120 milliseconds. The intention is to allow for bursts of data and protection against other processes hogging cpu time. I haven't seen a process locked out for more than 100 milliseconds. Making the buffer bigger uses a LOT of memory at the more frequent sampling rates as shown in the following table in MBs. buffer millisecondsint gpioCfgClock(unsigned cfgMicros, unsigned cfgPeripheral, unsigned cfgSource)Configures pigpio to use a particular sample rate timed by a specified peripheral.This function is only effective if called before gpioInitialise. cfgMicros: 1, 2, 4, 5, 8, 10The timings are provided by the specified peripheral (PWM or PCM). The default setting is 5 microseconds using the PCM peripheral. The approximate CPU percentage used for each sample rate is: sample cpuA sample rate of 5 microseconds seeems to be the sweet spot. int gpioCfgDMAchannel(unsigned DMAchannel)Configures pigpio to use the specified DMA channel.This function is only effective if called before gpioInitialise. DMAchannel: 0-14The default setting is to use channel 14. int gpioCfgDMAchannels(unsigned primaryChannel, unsigned secondaryChannel)Configures pigpio to use the specified DMA channels.This function is only effective if called before gpioInitialise. primaryChannel: 0-14The default setting depends on whether the Pi has a BCM2711 chip or not (currently only the Pi4B has a BCM2711). The default setting for a non-BCM2711 is to use channel 14 for the primary channel and channel 6 for the secondary channel. The default setting for a BCM2711 is to use channel 7 for the primary channel and channel 6 for the secondary channel. The secondary channel is only used for the transmission of waves. If possible use one of channels 0 to 6 for the secondary channel (a full channel). A full channel only requires one DMA control block regardless of the length of a pulse delay. Channels 7 to 14 (lite channels) require one DMA control block for each 16383 microseconds of delay. I.e. a 10 second pulse delay requires one control block on a full channel and 611 control blocks on a lite channel. int gpioCfgPermissions(uint64_t updateMask)Configures pigpio to restrict GPIO updates via the socket or pipe interfaces to the GPIO specified by the mask. Programs directly calling the pigpio library (i.e. linked with -lpigpio are not affected). A GPIO update is a write to a GPIO or a GPIO mode change or any function which would force such an action.This function is only effective if called before gpioInitialise. updateMask: bit (1<<n) is set for each GPIO n which may be updatedThe default setting depends upon the Pi model. The user GPIO are added to the mask. If the board revision is not recognised then GPIO 2-27 are allowed.
int gpioCfgSocketPort(unsigned port)Configures pigpio to use the specified socket port.This function is only effective if called before gpioInitialise. port: 1024-32000The default setting is to use port 8888. int gpioCfgInterfaces(unsigned ifFlags)Configures pigpio support of the fifo and socket interfaces.This function is only effective if called before gpioInitialise. ifFlags: 0-7The default setting (0) is that both interfaces are enabled. Or in PI_DISABLE_FIFO_IF to disable the pipe interface. Or in PI_DISABLE_SOCK_IF to disable the socket interface. Or in PI_LOCALHOST_SOCK_IF to disable remote socket access (this means that the socket interface is only usable from the local Pi). int gpioCfgMemAlloc(unsigned memAllocMode)Selects the method of DMA memory allocation.This function is only effective if called before gpioInitialise. memAllocMode: 0-2There are two methods of DMA memory allocation. The original method uses the /proc/self/pagemap file to allocate bus memory. The new method uses the mailbox property interface to allocate bus memory. Auto will use the mailbox method unless a larger than default buffer size is requested with gpioCfgBufferSize. int gpioCfgNetAddr(int numSockAddr, uint32_t *sockAddr)Sets the network addresses which are allowed to talk over the socket interface.This function is only effective if called before gpioInitialise. numSockAddr: 0-256 (0 means all addresses allowed)int gpioCfgInternals(unsigned cfgWhat, unsigned cfgVal)Used to tune internal settings.cfgWhat: see source codeuint32_t gpioCfgGetInternals(void)This function returns the current library internal configuration settings.int gpioCfgSetInternals(uint32_t cfgVal)This function sets the current library internal configuration settings.cfgVal: see source codeint gpioCustom1(unsigned arg1, unsigned arg2, char *argx, unsigned argc)This function is available for user customisation.It returns a single integer value. arg1: >=0Returns >= 0 if OK, less than 0 indicates a user defined error. int gpioCustom2(unsigned arg1, char *argx, unsigned argc, char *retBuf, unsigned retMax)This function is available for user customisation.It differs from gpioCustom1 in that it returns an array of bytes rather than just an integer. The returned value is an integer indicating the number of returned bytes. arg1: >=0Returns >= 0 if OK, less than 0 indicates a user defined error. The number of returned bytes must be retMax or less. int rawWaveAddSPI(rawSPI_t *spi, unsigned offset, unsigned spiSS, char *buf, unsigned spiTxBits, unsigned spiBitFirst, unsigned spiBitLast, unsigned spiBits)This function adds a waveform representing SPI data to the existing waveform (if any). spi: a pointer to a spi objectReturns the new total number of pulses in the current waveform if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_SER_OFFSET, or PI_TOO_MANY_PULSES. Not intended for general use. int rawWaveAddGeneric(unsigned numPulses, rawWave_t *pulses)This function adds a number of pulses to the current waveform.numPulses: the number of pulsesReturns the new total number of pulses in the current waveform if OK, otherwise PI_TOO_MANY_PULSES. The advantage of this function over gpioWaveAddGeneric is that it allows the setting of the flags field. The pulses are interleaved in time order within the existing waveform (if any). Merging allows the waveform to be built in parts, that is the settings for GPIO#1 can be added, and then GPIO#2 etc. If the added waveform is intended to start after or within the existing waveform then the first pulse should consist of a delay. Not intended for general use. unsigned rawWaveCB(void)Returns the number of the cb being currently output.Not intended for general use. rawCbs_t *rawWaveCBAdr(int cbNum)Return the (Linux) address of contol block cbNum.cbNum: the cb of interestNot intended for general use. uint32_t rawWaveGetOOL(int pos)Gets the OOL parameter stored at pos.pos: the position of interest.Not intended for general use. void rawWaveSetOOL(int pos, uint32_t lVal)Sets the OOL parameter stored at pos to value. pos: the position of interestNot intended for general use. uint32_t rawWaveGetOut(int pos)Gets the wave output parameter stored at pos.DEPRECATED: use rawWaveGetOOL instead. pos: the position of interest.Not intended for general use. void rawWaveSetOut(int pos, uint32_t lVal)Sets the wave output parameter stored at pos to value.DEPRECATED: use rawWaveSetOOL instead. pos: the position of interestNot intended for general use. uint32_t rawWaveGetIn(int pos)Gets the wave input value parameter stored at pos.DEPRECATED: use rawWaveGetOOL instead. pos: the position of interestNot intended for general use. void rawWaveSetIn(int pos, uint32_t lVal)Sets the wave input value stored at pos to value.DEPRECATED: use rawWaveSetOOL instead. pos: the position of interestNot intended for general use. rawWaveInfo_t rawWaveInfo(int wave_id)Gets details about the wave with id wave_id.wave_id: the wave of interestNot intended for general use. int getBitInBytes(int bitPos, char *buf, int numBits)Returns the value of the bit bitPos bits from the start of buf. Returns 0 if bitPos is greater than or equal to numBits. bitPos: bit index from the start of bufvoid putBitInBytes(int bitPos, char *buf, int bit)Sets the bit bitPos bits from the start of buf to bit.bitPos: bit index from the start of bufdouble time_time(void)Return the current time in seconds since the Epoch.void time_sleep(double seconds)Delay execution for a given number of secondsseconds: the number of seconds to sleepvoid rawDumpWave(void)Used to print a readable version of the current waveform to stderr.Not intended for general use. void rawDumpScript(unsigned script_id)Used to print a readable version of a script to stderr.script_id: >=0, a script_id returned by gpioStoreScriptNot intended for general use. PARAMETERSactive: 0-1000000The number of microseconds level changes are reported for once a noise filter has been triggered (by steady microseconds of a stable level).arg1An unsigned argument passed to a user customised function. Its meaning is defined by the customiser.arg2An unsigned argument passed to a user customised function. Its meaning is defined by the customiser.argcThe count of bytes passed to a user customised function.*argxA pointer to an array of bytes passed to a user customised function. Its meaning and content is defined by the customiser.baudThe speed of serial communication (I2C, SPI, serial link, waves) in bits per second.bitA value of 0 or 1.bitPosA bit position within a byte or word. The least significant bit is position 0.bitsA value used to select GPIO. If bit n of bits is set then GPIO n is selected.A convenient way to set bit n is to or in (1<<n). e.g. to select bits 5, 9, 23 you could use (1<<5) | (1<<9) | (1<<23). *bsc_xferA pointer to a bsc_xfer_t object used to control a BSC transfer.bsc_xfer_ttypedef struct*bufA buffer to hold data being sent or being received.bufSizeThe size in bytes of a buffer.bVal: 0-255 (Hex 0x0-0xFF, Octal 0-0377)An 8-bit byte value.cbNumA number identifying a DMA contol block.cfgMicrosThe GPIO sample rate in microseconds. The default is 5us, or 200 thousand samples per second.cfgMillis: 100-10000The size of the sample buffer in milliseconds. Generally this should be left at the default of 120ms. If you expect intense bursts of signals it might be necessary to increase the buffer size.cfgPeripheralOne of the PWM or PCM peripherals used to pace DMA transfers for timing purposes.cfgSourceDeprecated.cfgValA number specifying the value of a configuration item. See cfgWhat.cfgWhatA number specifying a configuration item.562484977: print enhanced statistics at termination. 984762879: set the initial debug level. charA single character, an 8 bit quantity able to store 0-255.clkfreq: 4689-250M (13184-375M for the BCM2711)The hardware clock frequency.PI_HW_CLK_MIN_FREQ 4689countThe number of bytes to be transferred in an I2C, SPI, or Serial command.CSThe GPIO used for the slave select signal when bit banging SPI.data_bits: 1-32The number of data bits to be used when adding serial data to a waveform.PI_MIN_WAVE_DATABITS 1DMAchannel: 0-15PI_MIN_DMA_CHANNEL 0doubleA floating point number.dutycycle: 0-rangeA number representing the ratio of on time to off time for PWM.The number may vary between 0 and range (default 255) where 0 is off and range is fully on. edge: 0-2The type of GPIO edge to generate an interrupt. See gpioSetISRFunc and gpioSetISRFuncEx.RISING_EDGE 0event: 0-31An event is a signal used to inform one or more consumers to start an action.eventFunc_ttypedef void (*eventFunc_t) (int event, uint32_t tick);eventFuncEx_ttypedef void (*eventFuncEx_t)fA function.*fileA full file path. To be accessible the path must match an entry in /opt/pigpio/access.*fpatA file path which may contain wildcards. To be accessible the path must match an entry in /opt/pigpio/access.frequency: >=0The number of times a GPIO is swiched on and off per second. This can be set per GPIO and may be as little as 5Hz or as much as 40KHz. The GPIO will be on for a proportion of the time as defined by its dutycycle.gpioA Broadcom numbered GPIO, in the range 0-53.There are 54 General Purpose Input Outputs (GPIO) named GPIO0 through GPIO53. They are split into two banks. Bank 1 consists of GPIO0 through GPIO31. Bank 2 consists of GPIO32 through GPIO53. All the GPIO which are safe for the user to read and write are in bank 1. Not all GPIO in bank 1 are safe though. Type 1 boards have 17 safe GPIO. Type 2 boards have 21. Type 3 boards have 26. See gpioHardwareRevision. The user GPIO are marked with an X in the following table. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15gpioAlertFunc_ttypedef void (*gpioAlertFunc_t) (int gpio, int level, uint32_t tick);gpioAlertFuncEx_ttypedef void (*eventFuncEx_t)gpioCfg*These functions are only effective if called before gpioInitialise.gpioCfgBufferSize gpioCfgClock gpioCfgDMAchannel gpioCfgDMAchannels gpioCfgPermissions gpioCfgInterfaces gpioCfgSocketPort gpioCfgMemAlloc gpioGetSamplesFunc_ttypedef void (*gpioGetSamplesFunc_t)gpioGetSamplesFuncEx_ttypedef void (*gpioGetSamplesFuncEx_t)gpioISRFunc_ttypedef void (*gpioISRFunc_t)gpioISRFuncEx_ttypedef void (*gpioISRFuncEx_t)gpioPulse_ttypedef structgpioSample_ttypedef structgpioSignalFunc_ttypedef void (*gpioSignalFunc_t) (int signum);gpioSignalFuncEx_ttypedef void (*gpioSignalFuncEx_t) (int signum, void *userdata);gpioThreadFunc_ttypedef void *(gpioThreadFunc_t) (void *);gpioTimerFunc_ttypedef void (*gpioTimerFunc_t) (void);gpioTimerFuncEx_ttypedef void (*gpioTimerFuncEx_t) (void *userdata);gpioWaveAdd*One ofgpioWaveAddNew gpioWaveAddGeneric gpioWaveAddSerial handle: >=0A number referencing an object opened by one offileOpen gpioNotifyOpen i2cOpen serOpen spiOpen i2cAddr: 0-0x7FThe address of a device on the I2C bus.i2cBus: >=0An I2C bus number.i2cFlags: 0Flags which modify an I2C open command. None are currently defined.i2cReg: 0-255A register of an I2C device.ifFlags: 0-3PI_DISABLE_FIFO_IF 1*inBufA buffer used to pass data to a function.inLenThe number of bytes of data in a buffer.intA whole number, negative or positive.int32_tA 32-bit signed value.invertA flag used to set normal or inverted bit bang serial data level logic.levelThe level of a GPIO. Low or High.PI_OFF 0There is one exception. If a watchdog expires on a GPIO the level will be reported as PI_TIMEOUT. See gpioSetWatchdog. PI_TIMEOUT 2lVal: 0-4294967295 (Hex 0x0-0xFFFFFFFF, Octal 0-37777777777)A 32-bit word value.memAllocMode: 0-2The DMA memory allocation mode.PI_MEM_ALLOC_AUTO 0*microsA value representing microseconds.microsA value representing microseconds.millisA value representing milliseconds.MISOThe GPIO used for the MISO signal when bit banging SPI.mode1. The operational mode of a GPIO, normally INPUT or OUTPUT.PI_INPUT 02. A file open mode. PI_FILE_READ 1The following values can be or'd into the mode. PI_FILE_APPEND 4MOSIThe GPIO used for the MOSI signal when bit banging SPI.numBitsThe number of bits stored in a buffer.numBytesThe number of bytes used to store characters in a string. Depending on the number of bits per character there may be 1, 2, or 4 bytes per character.numPar: 0-10The number of parameters passed to a script.numPulsesThe number of pulses to be added to a waveform.numSegsThe number of segments in a combined I2C transaction.numSockAddrThe number of network addresses allowed to use the socket interface.0 means all addresses allowed. offsetThe associated data starts this number of microseconds from the start of the waveform.*outBufA buffer used to return data from a function.outLenThe size in bytes of an output buffer.pad: 0-2A set of GPIO which share common drivers.
padStrength: 1-16The mA which may be drawn from each GPIO whilst still guaranteeing the high and low levels.*paramAn array of script parameters.pctBOOL: 0-100percent On-Off-Level (OOL) buffer to consume for wave output.pctCB: 0-100the percent of all DMA control blocks to consume.pctTOOL: 0-100the percent of OOL buffer to consume for wave input (flags).pi_i2c_msg_ttypedef structport: 1024-32000The port used to bind to the pigpio socket. Defaults to 8888.posThe position of an item.primaryChannel: 0-15The DMA channel used to time the sampling of GPIO and to time servo and PWM pulses.*pthA thread identifier, returned by gpioStartThread.pthread_tA thread identifier.pud: 0-2The setting of the pull up/down resistor for a GPIO, which may be off, pull-up, or pull-down.PI_PUD_OFF 0pulseLen1-100, the length of a trigger pulse in microseconds.*pulsesAn array of pulses to be added to a waveform.pulsewidth: 0, 500-2500PI_SERVO_OFF 0PWMduty: 0-1000000 (1M)The hardware PWM dutycycle.PI_HW_PWM_RANGE 1000000PWMfreq: 1-125M (1-187.5M for the BCM2711)The hardware PWM frequency.PI_HW_PWM_MIN_FREQ 1range: 25-40000PI_MIN_DUTYCYCLE_RANGE 25rawCbs_ttypedef struct // linux/arch/arm/mach-bcm2708/include/mach/dma.hrawSPI_ttypedef structrawWave_ttypedef structrawWaveInfo_ttypedef struct*retBufA buffer to hold a number of bytes returned to a used customised function,retMaxThe maximum number of bytes a user customised function should return.*rxBufA pointer to a buffer to receive data.SCLThe user GPIO to use for the clock when bit banging I2C.SCLKThe GPIO used for the SCLK signal when bit banging SPI.*scriptA pointer to the text of a script.script_idAn id of a stored script as returned by gpioStoreScript.*scriptNameThe name of a shell script to be executed. The script must be present in /opt/pigpio/cgi and must have execute permission.*scriptStringThe string to be passed to a shell script to be executed.SDAThe user GPIO to use for data when bit banging I2C.secondaryChannel: 0-6The DMA channel used to time output waveforms.*secondsA pointer to a uint32_t to store the second component of a returned time.secondsThe number of seconds.seekFromPI_FROM_START 0seekOffsetThe number of bytes to move forward (positive) or backwards (negative) from the seek position (start, current, or end of file).*segsAn array of segments which make up a combined I2C transaction.serFlagsFlags which modify a serial open command. None are currently defined.*serttyThe name of a serial tty device, e.g. /dev/ttyAMA0, /dev/ttyUSB0, /dev/tty1.settingA value used to set a flag, 0 for false, non-zero for true.signum: 0-63PI_MIN_SIGNUM 0size_tA standard type used to indicate the size of an object in bytes.*sockAddrAn array of network addresses allowed to use the socket interface encoded as 32 bit numbers.E.g. address 192.168.1.66 would be encoded as 0x4201a8c0. *spiA pointer to a rawSPI_t structure.spiBitFirstGPIO reads are made from spiBitFirst to spiBitLast.spiBitLastGPIO reads are made from spiBitFirst to spiBitLast.spiBitsThe number of bits to transfer in a raw SPI transaction.spiChanA SPI channel, 0-2.spiFlagsSee spiOpen and bbSPIOpen.spiSSThe SPI slave select GPIO in a raw SPI transaction.spiTxBitsThe number of bits to transfer dring a raw SPI transactionsteady: 0-300000The number of microseconds level changes must be stable for before reporting the level changed (gpioGlitchFilter) or triggering the active part of a noise filter (gpioNoiseFilter).stop_bits: 2-8The number of (half) stop bits to be used when adding serial data to a waveform.PI_MIN_WAVE_HALFSTOPBITS 2*strAn array of characters.timeoutA GPIO level change timeout in milliseconds.gpioSetWatchdog PI_MIN_WDOG_TIMEOUT 0gpioSetISRFunc and gpioSetISRFuncEx <=0 cancel timeouttimerPI_MIN_TIMER 0timetypePI_TIME_RELATIVE 0*txBufAn array of bytes to transmit.uint32_t: 0-0-4,294,967,295 (Hex 0x0-0xFFFFFFFF)A 32-bit unsigned value.uint64_t: 0-(2^64)-1A 64-bit unsigned value.unsignedA whole number >= 0.updateMaskA 64 bit mask indicating which GPIO may be written to by the user.If GPIO#n may be written then bit (1<<n) is set. user_gpio0-31, a Broadcom numbered GPIO.See gpio. *userdataA pointer to arbitrary user data. This may be used to identify the instance.You must ensure that the pointer is in scope at the time it is processed. If it is a pointer to a global this is automatic. Do not pass the address of a local variable. If you want to pass a transient object then use the following technique. In the calling function: user_type *userdata;In the receiving function: user_type my_userdata = *(user_type*)userdata;voidDenoting no parameter is requiredwave_idA number identifying a waveform created by gpioWaveCreate.wave_modeThe mode determines if the waveform is sent once or cycles repeatedly. The SYNC variants wait for the current waveform to reach the end of a cycle or finish before starting the new waveform.PI_WAVE_MODE_ONE_SHOT 0wVal: 0-65535 (Hex 0x0-0xFFFF, Octal 0-0177777)A 16-bit word value.Socket Command CodesError CodesDefaults |
[pigpio]
[pigpio C I/F]
[pigpiod]
[pigpiod C I/F]
[Python]
[pigs]
[piscope]
[Misc]
[Examples]
[Download]
[FAQ]
[Site Map]
© 2012-2020 |
e-mail: pigpio @ abyz.me.uk |
Updated: 30/04/2020 |