<br><br>pigpiod_if2 is a C library for the Raspberry which allows control
of the GPIO via the socket interface to the pigpio daemon.<br>
<h3>Features</h3>o hardware timed PWM on any of GPIO 0-31
<br><br>o hardware timed servo pulses on any of GPIO 0-31
<br><br>o callbacks when any of GPIO 0-31 change state
<br><br>o callbacks at timed intervals
<br><br>o reading/writing all of the GPIO in a bank as one operation
<br><br>o individually setting GPIO modes, reading and writing
<br><br>o notifications when any of GPIO 0-31 change state
<br><br>o the construction of output waveforms with microsecond timing
<br><br>o rudimentary permission control over GPIO
<br><br>o a simple interface to start and stop new threads
<br><br>o I2C, SPI, and serial link wrappers
<br><br>o creating and running scripts on the pigpio daemon
<h3>GPIO</h3>ALL GPIO are identified by their Broadcom number.
<h3>Notes</h3>The PWM and servo pulses are timed using the DMA and PWM/PCM peripherals.
<h3>Usage</h3>Include <pigpiod_if2.h> in your source files.
<br><br>Assuming your source is in prog.c use the following command to build
<br><br><code>gcc -Wall -pthread -o prog prog.c -lpigpiod_if2 -lrt<br></code><br><br>to run make sure the pigpio daemon is running
<br><br><code>sudo pigpiod<br><br> ./prog # sudo is not required to run programs linked to pigpiod_if2<br></code><br><br>For examples see x_pigpiod_if2.c within the pigpio archive file.
<h3>Notes</h3>All the functions which return an int return < 0 on error
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#gpio_read">gpio_read</a></td><td> Read a GPIO
</td></tr><tr><td><a href="#gpio_write">gpio_write</a></td><td> Write a GPIO
</td></tr><tr><td></td><td></td></tr><tr><td><b>PWM (overrides servo commands on same GPIO)
</b></td><td></td></tr><tr><td></td><td></td></tr><tr><td><a href="#set_PWM_dutycycle">set_PWM_dutycycle</a></td><td> Start/stop PWM pulses on a GPIO
</td></tr><tr><td><a href="#set_PWM_frequency">set_PWM_frequency</a></td><td> Configure PWM frequency for a GPIO
</td></tr><tr><td><a href="#set_PWM_range">set_PWM_range</a></td><td> Configure PWM range for a GPIO
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#get_PWM_dutycycle">get_PWM_dutycycle</a></td><td> Get the PWM dutycycle in use on a GPIO
</td></tr><tr><td><a href="#get_PWM_frequency">get_PWM_frequency</a></td><td> Get configured PWM frequency for a GPIO
</td></tr><tr><td><a href="#get_PWM_range">get_PWM_range</a></td><td> Get configured PWM range for a GPIO
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#get_PWM_real_range">get_PWM_real_range</a></td><td> Get underlying PWM range for a GPIO
</td></tr><tr><td></td><td></td></tr><tr><td><b>Servo (overrides PWM commands on same GPIO)
</b></td><td></td></tr><tr><td></td><td></td></tr><tr><td><a href="#set_servo_pulsewidth">set_servo_pulsewidth</a></td><td> Start/stop servo pulses on a GPIO
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#get_servo_pulsewidth">get_servo_pulsewidth</a></td><td> Get the servo pulsewidth in use on a GPIO
</b></td><td></td></tr><tr><td></td><td></td></tr><tr><td><a href="#serial_open">serial_open</a></td><td> Opens a serial device
</td></tr><tr><td><a href="#serial_close">serial_close</a></td><td> Closes a serial device
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#serial_read_byte">serial_read_byte</a></td><td> Reads a byte from a serial device
</td></tr><tr><td><a href="#serial_write_byte">serial_write_byte</a></td><td> Writes a byte to a serial device
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#serial_read">serial_read</a></td><td> Reads bytes from a serial device
</td></tr><tr><td><a href="#serial_write">serial_write</a></td><td> Writes bytes to a serial device
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#serial_data_available">serial_data_available</a></td><td> Returns number of bytes ready to be read
</td></tr><tr><td></td><td></td></tr><tr><td><b>SERIAL BIT BANG (read only)
</b></td><td></td></tr><tr><td></td><td></td></tr><tr><td><a href="#bb_serial_read_open">bb_serial_read_open</a></td><td> Opens a GPIO for bit bang serial reads
</td></tr><tr><td><a href="#bb_serial_read_close">bb_serial_read_close</a></td><td> Closes a GPIO for bit bang serial reads
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#bb_serial_invert">bb_serial_invert</a></td><td> Invert serial logic (1 invert, 0 normal)
</td></tr><tr><td></td><td></td></tr><tr><td><a href="#bb_serial_read">bb_serial_read</a></td><td> Reads bit bang serial data from a GPIO
Starts a new thread of execution with thread_func as the main routine.
<br><br><code>thread_func: the main function for the new thread.<br> userdata: a pointer to an arbitrary argument.<br></code><br><br>Returns a pointer to pthread_t if OK, otherwise NULL.
<br><br>The function is passed the single argument userdata.
<br><br>The thread can be cancelled by passing the pointer to pthread_t to
Connect to the pigpio daemon. Reserving command and
notification streams.
<br><br><code>addrStr: specifies the host or IP address of the Pi running the<br> pigpio daemon. It may be NULL in which case localhost<br> is used unless overridden by the PIGPIO_ADDR environment<br> variable.<br><br>portStr: specifies the port address used by the Pi running the<br> pigpio daemon. It may be NULL in which case "8888"<br> is used unless overridden by the PIGPIO_PORT environment<br> variable.<br></code><br><br>Returns an integer value greater than or equal to zero if OK.
<br><br>This value is passed to the GPIO routines to specify the Pi
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>gpio: 0-53.<br></code><br><br>Returns the GPIO mode if OK, otherwise PI_BAD_GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>gpio:0-53.<br></code><br><br>Returns the GPIO level if OK, otherwise PI_BAD_GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO or PI_NOT_PWM_GPIO.
<br><br>For normal PWM the dutycycle will be out of the defined range
for the GPIO (see <a href="#get_PWM_range">get_PWM_range</a>).
<br><br>If a hardware clock is active on the GPIO the reported dutycycle
will be 500000 (500k) out of 1000000 (1M).
<br><br>If hardware PWM is active on the GPIO the reported dutycycle
Set the range of PWM values to be used on the GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br> range: 25-40000.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_DUTYRANGE,
or PI_NOT_PERMITTED.
<br><br>Notes
<br><br>If PWM is currently active on the GPIO its dutycycle will be
scaled to reflect the new range.
<br><br>The real range, the number of steps between fully off and fully on
for each of the 18 available GPIO frequencies is
<br><br><code> 25(#1), 50(#2), 100(#3), 125(#4), 200(#5), 250(#6),<br> 400(#7), 500(#8), 625(#9), 800(#10), 1000(#11), 1250(#12),<br>2000(#13), 2500(#14), 4000(#15), 5000(#16), 10000(#17), 20000(#18)<br></code><br><br>The real value set by set_PWM_range is (dutycycle * real range) / range.
Get the range of PWM values being used on the GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br></code><br><br>Returns the dutycycle range used for the GPIO if OK,
otherwise PI_BAD_USER_GPIO.
<br><br>If a hardware clock or hardware PWM is active on the GPIO the
Get the real underlying range of PWM values being used on the GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br></code><br><br>Returns the real range used for the GPIO if OK,
otherwise PI_BAD_USER_GPIO.
<br><br>If a hardware clock is active on the GPIO the reported
real range will be 1000000 (1M).
<br><br>If hardware PWM is active on the GPIO the reported real range
will be approximately 250M divided by the set PWM frequency.
Set the frequency (in Hz) of the PWM to be used on the GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br>frequency: >=0 (Hz).<br></code><br><br>Returns the numerically closest frequency if OK, otherwise
PI_BAD_USER_GPIO or PI_NOT_PERMITTED.
<br><br>If PWM is currently active on the GPIO it will be switched
off and then back on at the new frequency.
<br><br>Each GPIO can be independently set to one of 18 different
PWM frequencies.
<br><br>The selectable frequencies depend upon the sample rate which
may be 1, 2, 4, 5, 8, or 10 microseconds (default 5). The
sample rate is set when the pigpio daemon is started.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br></code><br><br>For normal PWM the frequency will be that defined for the GPIO by
Start (500-2500) or stop (0) servo pulses on the GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> user_gpio: 0-31.<br>pulsewidth: 0 (off), 500 (anti-clockwise) - 2500 (clockwise).<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_PULSEWIDTH or
PI_NOT_PERMITTED.
<br><br>The selected pulsewidth will continue to be transmitted until
changed by a subsequent call to set_servo_pulsewidth.
<br><br>The pulsewidths 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.
<br><br>You can DAMAGE a servo if you command it to move beyond its limits.
<br><br>OTHER UPDATE RATES:
<br><br>This function updates servos at 50Hz. If you wish to use a different
update frequency you will have to use the PWM functions.
<br><br><code>Update Rate (Hz) 50 100 200 400 500<br>1E6/Hz 20000 10000 5000 2500 2000<br></code><br><br>Firstly set the desired PWM frequency using <a href="#set_PWM_frequency">set_PWM_frequency</a>.
<br><br>Then set the PWM range using <a href="#set_PWM_range">set_PWM_range</a> to 1E6/Hz.
Doing this allows you to use units of microseconds when setting
the servo pulsewidth.
<br><br>E.g. If you want to update a servo connected to GPIO 25 at 400Hz
<br><br><code>set_PWM_frequency(25, 400);<br>set_PWM_range(25, 2500);<br></code><br><br>Thereafter use the <a href="#set_PWM_dutycycle">set_PWM_dutycycle</a> function to move the servo,
e.g. set_PWM_dutycycle(25, 1500) will set a 1500 us pulse.<br>
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO or PI_NOT_SERVO_GPIO.
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>Returns a handle greater than or equal to zero if OK,
otherwise PI_NO_HANDLE.
<br><br>A notification is a method for being notified of GPIO state
changes via a pipe.
<br><br>Pipes are only accessible from the local machine so this function
serves no purpose if you are using the library from a remote machine.
The in-built (socket) notifications provided by <a href="#callback">callback</a>
should be used instead.
<br><br>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
Start notifications on a previously opened handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: 0-31 (as returned by <a href="#notify_open">notify_open</a>)<br> bits: a mask indicating the GPIO to be notified.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE.
<br><br>The notification sends state changes for each GPIO whose
corresponding bit in bits is set.
<br><br>Each notification occupies 12 bytes in the fifo as follows:
<br><br><code>typedef struct<br>{<br> uint16_t seqno;<br> uint16_t flags;<br> uint32_t tick;<br> uint32_t level;<br>} gpioReport_t;<br></code><br><br>seqno: starts at 0 each time the handle is opened and then increments
by one for each report.
<br><br>flags: three flags are defined, PI_NTFY_FLAGS_WDOG,
PI_NTFY_FLAGS_ALIVE, and PI_NTFY_FLAGS_EVENT.
<br><br>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.
<br><br>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.
<br><br>If bit 7 is set (PI_NTFY_FLAGS_EVENT) then bits 0-4 of the flags
indicate an event which has been triggered.
<br><br>tick: the number of microseconds since system boot. It wraps around
after 1h12m.
<br><br>level: indicates the level of each GPIO. If bit 1<<x is set then
<br><br>Level changes on the GPIO are not reported unless the level
has been stable for at least <a href="#steady">steady</a> microseconds. The
level is then reported. Level changes of less than
<a href="#steady">steady</a> microseconds are ignored.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31<br> steady: 0-300000<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_BAD_FILTER.
<br><br>This filter affects the GPIO samples returned to callbacks set up
with <a href="#callback">callback</a>, <a href="#callback_ex">callback_ex</a> and <a href="#wait_for_edge">wait_for_edge</a>.
<br><br>It does not affect levels read by <a href="#gpio_read">gpio_read</a>,
<a href="#read_bank_1">read_bank_1</a>, or <a href="#read_bank_2">read_bank_2</a>.
<br><br>Each (stable) edge will be timestamped <a href="#steady">steady</a> microseconds
<br><br>Level changes on the GPIO are ignored until a level which has
been stable for <a href="#steady">steady</a> microseconds is detected. Level changes
on the GPIO are then reported for <a href="#active">active</a> microseconds after
which the process repeats.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31<br> steady: 0-300000<br> active: 0-1000000<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_BAD_FILTER.
<br><br>This filter affects the GPIO samples returned to callbacks set up
with <a href="#callback">callback</a>, <a href="#callback_ex">callback_ex</a> and <a href="#wait_for_edge">wait_for_edge</a>.
<br><br>It does not affect levels read by <a href="#gpio_read">gpio_read</a>,
<a href="#read_bank_1">read_bank_1</a>, or <a href="#read_bank_2">read_bank_2</a>.
<br><br>Level changes before and after the active period may
be reported. Your software must be designed to cope with
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>The returned 32 bit integer has a bit set if the corresponding
GPIO is logic 1. GPIO n has bit value (1<<n).
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>The returned 32 bit integer has a bit set if the corresponding
GPIO is logic 1. GPIO n has bit value (1<<(n-32)).
<br><br>The same clock is available on multiple GPIO. The latest
frequency setting will be used by all GPIO which share a clock.
<br><br>The GPIO must be one of the following.
<br><br><code>4 clock 0 All models<br>5 clock 1 All models but A and B (reserved for system use)<br>6 clock 2 All models but A and B<br>20 clock 0 All models but A and B<br>21 clock 1 All models but A and Rev.2 B (reserved for system use)<br><br>32 clock 0 Compute module only<br>34 clock 0 Compute module only<br>42 clock 1 Compute module only (reserved for system use)<br>43 clock 2 Compute module only<br>44 clock 1 Compute module only (reserved for system use)<br></code><br><br>Access 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
<br><br>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.
<br><br>The GPIO must be one of the following.
<br><br><code>12 PWM channel 0 All models but A and B<br>13 PWM channel 1 All models but A and B<br>18 PWM channel 0 All models<br>19 PWM channel 1 All models but A and B<br><br>40 PWM channel 0 Compute module only<br>41 PWM channel 1 Compute module only<br>45 PWM channel 1 Compute module only<br>52 PWM channel 0 Compute module only<br>53 PWM channel 1 Compute module only<br></code><br><br>The actual number of steps beween off and fully on is the
integral part of 250M/PWMfreq (375M/PWMfreq for the BCM2711).
<br><br>The actual frequency set is 250M/steps (375M/steps for the BCM2711).
<br><br>There will only be a million steps for a PWMfreq of 250 (375 for
the BCM2711). Lower frequencies will have more steps and higher
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>Tick is the number of microseconds since system boot.
<br><br>As tick is an unsigned 32 bit quantity it wraps around after
2**32 microseconds, which is approximately 1 hour 12 minutes.
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>The hardware revision is the last few characters on the Revision line
of /proc/cpuinfo.
<br><br>If the hardware revision can not be found or is not a valid
hexadecimal number the function returns 0.
<br><br>The revision number can be used to determine the assignment of GPIO
to pins (see <a href="#gpio">gpio</a>).
<br><br>There are at least three types of board.
<br><br>Type 1 boards have hardware revision numbers of 2 and 3.
<br><br>Type 2 boards have hardware revision numbers of 4, 5, 6, and 15.
<br><br>Type 3 boards have hardware revision numbers of 16 or greater.
This function adds a number of pulses to the current waveform.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>numPulses: the number of pulses.<br> pulses: an array of pulses.<br></code><br><br>Returns the new total number of pulses in the current waveform if OK,
otherwise PI_TOO_MANY_PULSES.
<br><br>The pulses are interleaved in time order within the existing waveform
(if any).
<br><br>Merging allows the waveform to be built in parts, that is the settings
for GPIO#1 can be added, and then GPIO#2 etc.
<br><br>If the added waveform is intended to start after or within the existing
waveform then the first pulse should consist solely of a delay.
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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br> baud: 50-1000000<br>data_bits: number of data bits (1-32)<br>stop_bits: number of stop half bits (2-8)<br> offset: >=0<br> numBytes: >=1<br> str: an array of chars.<br></code><br><br>Returns the new total number of pulses in the current waveform if OK,
This function creates a waveform from the data provided by the prior
calls to the <a href="#wave_add_*">wave_add_*</a> 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.
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>The data provided by the <a href="#wave_add_*">wave_add_*</a> functions is consumed by this
function.
<br><br>As many waveforms may be created as there is space available. The
wave id is passed to <a href="#wave_send_*">wave_send_*</a> to specify the waveform to transmit.
<br><br>Normal usage would be
<br><br>Step 1. <a href="#wave_clear">wave_clear</a> to clear all waveforms and added data.
<br><br>Step 2. <a href="#wave_add_*">wave_add_*</a> calls to supply the waveform data.
<br><br>Step 3. <a href="#wave_create">wave_create</a> to create the waveform and get a unique id
<br><br>Repeat steps 2 and 3 as needed.
<br><br>Step 4. <a href="#wave_send_*">wave_send_*</a> with the id of the waveform to transmit.
<br><br>A waveform comprises one or more pulses. Each pulse consists of a
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>percent: 0-100, size of waveform as percentage of maximum available.<br></code><br><br>The data provided by the <a href="#wave_add_*">wave_add_*</a> functions are consumed by this
This function deletes the waveform with id wave_id.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>wave_id: >=0, as returned by <a href="#wave_create">wave_create</a>.<br></code><br><br>Wave ids are allocated in order, 0, 1, 2, etc.
<br><br>The wave is flagged for deletion. The resources used by the wave
will only be reused when either of the following apply.
<br><br>- all waves with higher numbered wave ids have been deleted or have
been flagged for deletion.
<br><br>- a new wave is created which uses exactly the same resources as
the current wave (see the C source for gpioWaveCreate for details).
<br><br>Returns 0 if OK, otherwise PI_BAD_WAVE_ID.
This function transmits the waveform with id wave_id. The waveform
is sent once.
<br><br>NOTE: Any hardware PWM started by <a href="#hardware_PWM">hardware_PWM</a> will be cancelled.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>wave_id: >=0, as returned by <a href="#wave_create">wave_create</a>.<br></code><br><br>Returns the number of DMA control blocks in the waveform if OK,
This function transmits the waveform with id wave_id. The waveform
cycles until cancelled (either by the sending of a new waveform or
by <a href="#wave_tx_stop">wave_tx_stop</a>).
<br><br>NOTE: Any hardware PWM started by <a href="#hardware_PWM">hardware_PWM</a> will be cancelled.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>wave_id: >=0, as returned by <a href="#wave_create">wave_create</a>.<br></code><br><br>Returns the number of DMA control blocks in the waveform if OK,
Transmits the waveform with id wave_id using mode mode.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>wave_id: >=0, as returned by <a href="#wave_create">wave_create</a>.<br> mode: PI_WAVE_MODE_ONE_SHOT, PI_WAVE_MODE_REPEAT,<br> PI_WAVE_MODE_ONE_SHOT_SYNC, or PI_WAVE_MODE_REPEAT_SYNC.<br></code><br><br>PI_WAVE_MODE_ONE_SHOT: same as <a href="#wave_send_once">wave_send_once</a>.
<br><br>PI_WAVE_MODE_REPEAT same as <a href="#wave_send_repeat">wave_send_repeat</a>.
<br><br>PI_WAVE_MODE_ONE_SHOT_SYNC same as <a href="#wave_send_once">wave_send_once</a> but tries
to sync with the previous waveform.
<br><br>PI_WAVE_MODE_REPEAT_SYNC same as <a href="#wave_send_repeat">wave_send_repeat</a> but tries
to sync with the previous waveform.
<br><br>WARNING: bad things may happen if you delete the previous
waveform before it has been synced to the new waveform.
<br><br>NOTE: Any hardware PWM started by <a href="#hardware_PWM">hardware_PWM</a> will be cancelled.
<br><br>Returns the number of DMA control blocks in the waveform if OK,
PI_BAD_CHAIN_DELAY, PI_CHAIN_TOO_BIG, or PI_BAD_WAVE_ID.
<br><br>Each wave is transmitted in the order specified. A wave may
occur multiple times per chain.
<br><br>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.
<br><br>Delays between waves may be added with the delay command.
<br><br>The following command codes are supported:
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>Name</td><td>Cmd & Data</td><td>Meaning</td></tr><tr><td>Loop Start</td><td>255 0</td><td>Identify start of a wave block</td></tr><tr><td>Loop Repeat</td><td>255 1 x y</td><td>loop x + y*256 times</td></tr><tr><td>Delay</td><td>255 2 x y</td><td>delay x + y*256 microseconds</td></tr><tr><td>Loop Forever</td><td>255 3</td><td>loop forever</td></tr></tbody></table><br><br>If present Loop Forever must be the last entry in the chain.
<br><br>The code is currently dimensioned to support a chain with roughly
This function returns the id of the waveform currently being
transmitted.
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>Returns the waveform id or one of the following special values:
<br><br>PI_WAVE_NOT_FOUND (9998) - transmitted wave not found.<br>
This function checks to see if a waveform is currently being
transmitted.
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br></code><br><br>Returns 1 if a waveform is currently being transmitted, otherwise 0.
This function stores a script for later execution.
<br><br>See <a href="http://abyz.me.uk/rpi/pigpio/pigs.html#Scripts">http://abyz.me.uk/rpi/pigpio/pigs.html#Scripts</a> for details.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>script: the text of the script.<br></code><br><br>The function returns a script id if the script is valid,
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>script_id: >=0, as returned by <a href="#store_script">store_script</a>.<br> numPar: 0-10, the number of parameters.<br> param: an array of parameters.<br></code><br><br>The function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID, or
PI_TOO_MANY_PARAM
<br><br>param is an array of up to 10 parameters which may be referenced in
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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>script_id: >=0, as returned by <a href="#store_script">store_script</a>.<br> numPar: 0-10, the number of parameters.<br> param: an array of parameters.<br></code><br><br>The function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID, or
PI_TOO_MANY_PARAM.
<br><br>param is an array of up to 10 parameters which may be referenced in
This function returns the run status of a stored script as well
as the current values of parameters 0 to 9.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>script_id: >=0, as returned by <a href="#store_script">store_script</a>.<br> param: an array to hold the returned 10 parameters.<br></code><br><br>The function returns greater than or equal to 0 if OK,
otherwise PI_BAD_SCRIPT_ID.
<br><br>The run status may be
<br><br><code>PI_SCRIPT_INITING<br>PI_SCRIPT_HALTED<br>PI_SCRIPT_RUNNING<br>PI_SCRIPT_WAITING<br>PI_SCRIPT_FAILED<br></code><br><br>The current value of script parameters 0 to 9 are returned in param.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>script_id: >=0, as returned by <a href="#store_script">store_script</a>.<br></code><br><br>The function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>script_id: >=0, as returned by <a href="#store_script">store_script</a>.<br></code><br><br>The function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID.
This function copies up to bufSize bytes of data read from the
bit bang serial cyclic buffer to the buffer starting at buf.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31, previously opened with <a href="#bb_serial_read_open">bb_serial_read_open</a>.<br> buf: an array to receive the read bytes.<br> bufSize: >=0<br></code><br><br>Returns the number of bytes copied if OK, otherwise PI_BAD_USER_GPIO
or PI_NOT_SERIAL_GPIO.
<br><br>The bytes returned for each character depend upon the number of
data bits <a href="#data_bits">data_bits</a> specified in the <a href="#bb_serial_read_open">bb_serial_read_open</a> command.
<br><br>For <a href="#data_bits">data_bits</a> 1-8 there will be one byte per character.<br>
For <a href="#data_bits">data_bits</a> 9-16 there will be two bytes per character.<br>
For <a href="#data_bits">data_bits</a> 17-32 there will be four bytes per character.
This function closes a GPIO for bit bang reading of serial data.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31, previously opened with <a href="#bb_serial_read_open">bb_serial_read_open</a>.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_SERIAL_GPIO.
This function inverts serial logic for big bang serial reads.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31, previously opened with <a href="#bb_serial_read_open">bb_serial_read_open</a>.<br> invert: 0-1, 1 invert, 0 normal.<br></code><br><br>Returns 0 if OK, otherwise PI_NOT_SERIAL_GPIO or PI_BAD_SER_INVERT.
This returns a handle for the device at address i2c_addr on bus i2c_bus.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> i2c_bus: >=0.<br> i2c_addr: 0-0x7F.<br>i2c_flags: 0.<br></code><br><br>No flags are currently defined. This parameter should be set to zero.
<br><br>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.
<br><br>The GPIO used are given in the following table.
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td></td><td>SDA</td><td>SCL</td></tr><tr><td>I2C 0</td><td>0</td><td>1</td></tr><tr><td>I2C 1</td><td>2</td><td>3</td></tr></tbody></table><br><br>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.
<br><br>For the SMBus commands the low level transactions are shown at the end
of the function description. The following abbreviations are used.
This sends a single bit (in the Rd/Wr bit) to the device associated
with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br> bit: 0-1, the value to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This sends a single byte to the device associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br> bVal: 0-0xFF, the value to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This writes a single byte to the specified register of the device
associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to write.<br> bVal: 0-0xFF, the value to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This writes a single 16 bit word to the specified register of the device
associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to write.<br> wVal: 0-0xFFFF, the value to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This reads a single 16 bit word from the specified register of the device
associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to read.<br></code><br><br>Returns the word read (>=0) if OK, otherwise PI_BAD_HANDLE,
This writes 16 bits of data to the specified register of the device
associated with handle and and reads 16 bits of data in return.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to write/read.<br> wVal: 0-0xFFFF, the value to write.<br></code><br><br>Returns the word read (>=0) if OK, otherwise PI_BAD_HANDLE,
This writes up to 32 bytes to the specified register of the device
associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to write.<br> buf: an array with the data to send.<br> count: 1-32, the number of bytes to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This reads a block of up to 32 bytes from the specified register of
the device associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to read.<br> buf: an array to receive the read data.<br></code><br><br>The amount of returned data is set by the device.
<br><br>Returns the number of bytes read (>=0) if OK, otherwise PI_BAD_HANDLE,
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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to write/read.<br> buf: an array with the data to send and to receive the read data.<br> count: 1-32, the number of bytes to write.<br></code><br><br>Returns the number of bytes read (>=0) if OK, otherwise PI_BAD_HANDLE,
PI_BAD_PARAM, or PI_I2C_READ_FAILED.
<br><br>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
This reads count bytes from the specified register of the device
associated with handle . The count may be 1-32.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to read.<br> buf: an array to receive the read data.<br> count: 1-32, the number of bytes to read.<br></code><br><br>Returns the number of bytes read (>0) if OK, otherwise PI_BAD_HANDLE,
This writes 1 to 32 bytes to the specified register of the device
associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br>i2c_reg: 0-255, the register to write.<br> buf: the data to write.<br> count: 1-32, the number of bytes to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This writes count bytes from buf to the raw device.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#i2c_open">i2c_open</a>.<br> buf: an array containing the data bytes to write.<br> count: >0, the number of bytes to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#i2cOpen">i2cOpen</a><br> inBuf: pointer to the concatenated I2C commands, see below<br> inLen: size of command buffer<br>outBuf: pointer to buffer to hold returned data<br>outLen: size of output buffer<br></code><br><br>Returns >= 0 if OK (the number of bytes read), otherwise
<br><br>The following command codes are supported:
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>Name</td><td>Cmd & Data</td><td>Meaning</td></tr><tr><td>End</td><td>0</td><td>No more commands</td></tr><tr><td>Escape</td><td>1</td><td>Next P is two bytes</td></tr><tr><td>On</td><td>2</td><td>Switch combined flag on</td></tr><tr><td>Off</td><td>3</td><td>Switch combined flag off</td></tr><tr><td>Address</td><td>4 P</td><td>Set I2C address to P</td></tr><tr><td>Flags</td><td>5 lsb msb</td><td>Set I2C flags to lsb + (msb << 8)</td></tr><tr><td>Read</td><td>6 P</td><td>Read P bytes of data</td></tr><tr><td>Write</td><td>7 P ...</td><td>Write P bytes of data</td></tr></tbody></table><br><br>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).
<br><br>The address defaults to that associated with the handle.
The flags default to 0. The address and flags maintain their
previous value until updated.
<br><br>The returned I2C data is stored in consecutive locations of outBuf.
This function selects a pair of GPIO for bit banging I2C at a
specified baud rate.
<br><br>Bit banging I2C allows for certain operations which are not possible
with the standard I2C driver.
<br><br>o baud rates as low as 50<br>
o repeated starts<br>
o clock stretching<br>
o I2C on any pair of spare GPIO
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> SDA: 0-31<br> SCL: 0-31<br>baud: 50-500000<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_I2C_BAUD, or
PI_GPIO_IN_USE.
<br><br>NOTE:
<br><br>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.
This function stops bit banging I2C on a pair of GPIO previously
opened with <a href="#bb_i2c_open">bb_i2c_open</a>.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>SDA: 0-31, the SDA GPIO used in a prior call to <a href="#bb_i2c_open">bb_i2c_open</a><br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_I2C_GPIO.
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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> SDA: 0-31 (as used in a prior call to <a href="#bb_i2c_open">bb_i2c_open</a>)<br> inBuf: pointer to the concatenated I2C commands, see below<br> inLen: size of command buffer<br>outBuf: pointer to buffer to hold returned data<br>outLen: size of output buffer<br></code><br><br>Returns >= 0 if OK (the number of bytes read), otherwise
<br><br>The following command codes are supported:
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>Name</td><td>Cmd & Data</td><td>Meaning</td></tr><tr><td>End</td><td>0</td><td>No more commands</td></tr><tr><td>Escape</td><td>1</td><td>Next P is two bytes</td></tr><tr><td>Start</td><td>2</td><td>Start condition</td></tr><tr><td>Stop</td><td>3</td><td>Stop condition</td></tr><tr><td>Address</td><td>4 P</td><td>Set I2C address to P</td></tr><tr><td>Flags</td><td>5 lsb msb</td><td>Set I2C flags to lsb + (msb << 8)</td></tr><tr><td>Read</td><td>6 P</td><td>Read P bytes of data</td></tr><tr><td>Write</td><td>7 P ...</td><td>Write P bytes of data</td></tr></tbody></table><br><br>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).
<br><br>The address and flags default to 0. The address and flags maintain
their previous value until updated.
<br><br>No flags are currently defined.
<br><br>The returned I2C data is stored in consecutive locations of outBuf.
This function selects a set of GPIO for bit banging SPI at a
specified baud rate.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> CS: 0-31<br> MISO: 0-31<br> MOSI: 0-31<br> SCLK: 0-31<br> baud: 50-250000<br>spi_flags: see below<br></code><br><br>spi_flags consists of the least significant 22 bits.
<br><br><code>21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0<br> 0 0 0 0 0 0 R T 0 0 0 0 0 0 0 0 0 0 0 p m m<br></code><br><br>mm defines the SPI mode, defaults to 0
<br><br><code>Mode CPOL CPHA<br> 0 0 0<br> 1 0 1<br> 2 1 0<br> 3 1 1<br></code><br><br>p is 0 if CS is active low (default) and 1 for active high.
<br><br>T is 1 if the least significant bit is transmitted on MOSI first, the
default (0) shifts the most significant bit out first.
<br><br>R is 1 if the least significant bit is received on MISO first, the
default (0) receives the most significant bit first.
<br><br>The other bits in flags should be set to zero.
<br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_SPI_BAUD, or
PI_GPIO_IN_USE.
<br><br>If more than one device is connected to the SPI bus (defined by
This function stops bit banging SPI on a set of GPIO
opened with <a href="#bbSPIOpen">bbSPIOpen</a>.
<br><br><code>pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>CS: 0-31, the CS GPIO used in a prior call to <a href="#bb_spi_open">bb_spi_open</a><br></code><br><br>Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_SPI_GPIO.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> CS: 0-31 (as used in a prior call to <a href="#bb_spi_open">bb_spi_open</a>)<br>txBuf: pointer to buffer to hold data to be sent<br>rxBuf: pointer to buffer to hold returned data<br>count: size of data transfer<br></code><br><br>Returns >= 0 if OK (the number of bytes read), otherwise
PI_BAD_USER_GPIO, PI_NOT_SPI_GPIO or PI_BAD_POINTER.
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.
<br><br>The Pi has two SPI peripherals: main and auxiliary.
<br><br>The main SPI has two chip selects (channels), the auxiliary has
three.
<br><br>The auxiliary SPI is available on all models but the A and B.
<br><br>The GPIO used are given in the following table.
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td></td><td>MISO</td><td>MOSI</td><td>SCLK</td><td>CE0</td><td>CE1</td><td>CE2</td></tr><tr><td>Main SPI</td><td>9</td><td>10</td><td>11</td><td>8</td><td>7</td><td>-</td></tr><tr><td>Aux SPI</td><td>19</td><td>20</td><td>21</td><td>18</td><td>17</td><td>16</td></tr></tbody></table><br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>spi_channel: 0-1 (0-2 for the auxiliary SPI).<br> baud: 32K-125M (values above 30M are unlikely to work).<br> spi_flags: see below.<br></code><br><br>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.
<br><br>spi_flags consists of the least significant 22 bits.
<br><br><code>21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0<br> b b b b b b R T n n n n W A u2 u1 u0 p2 p1 p0 m m<br></code><br><br>mm defines the SPI mode.
<br><br>Warning: modes 1 and 3 do not appear to work on the auxiliary SPI.
<br><br><code>Mode POL PHA<br> 0 0 0<br> 1 0 1<br> 2 1 0<br> 3 1 1<br></code><br><br>px is 0 if CEx is active low (default) and 1 for active high.
<br><br>ux is 0 if the CEx GPIO is reserved for SPI (default) and 1 otherwise.
<br><br>A is 0 for the main SPI, 1 for the auxiliary SPI.
<br><br>W is 0 if the device is not 3-wire, 1 if the device is 3-wire. Main
SPI only.
<br><br>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.
<br><br>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.
<br><br>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.
<br><br>bbbbbb defines the word size in bits (0-32). The default (0)
sets 8 bits per word. Auxiliary SPI only.
<br><br>The <a href="#spi_read">spi_read</a>, <a href="#spi_write">spi_write</a>, and <a href="#spi_xfer">spi_xfer</a> functions
transfer data packed into 1, 2, or 4 bytes according to
the word size in bits.
<br><br>For bits 1-8 there will be one byte per character.<br>
For bits 9-16 there will be two bytes per character.<br>
For bits 17-32 there will be four bytes per character.
<br><br>Multi-byte transfers are made in least significant byte first order.
<br><br>E.g. to transfer 32 11-bit words buf should contain 64 bytes
and count should be 64.
<br><br>E.g. to transfer the 14 bit value 0x1ABC send the bytes 0xBC followed
by 0x1A.
<br><br>The other bits in flags should be set to zero.
This function reads count bytes of data from the SPI
device associated with the handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#spi_open">spi_open</a>.<br> buf: an array to receive the read data bytes.<br> count: the number of bytes to read.<br></code><br><br>Returns the number of bytes transferred if OK, otherwise
PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or PI_SPI_XFER_FAILED.
This function writes count bytes of data from buf to the SPI
device associated with the handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#spi_open">spi_open</a>.<br> buf: the data bytes to write.<br> count: the number of bytes to write.<br></code><br><br>Returns the number of bytes transferred if OK, otherwise
PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or PI_SPI_XFER_FAILED.
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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#spi_open">spi_open</a>.<br> txBuf: the data bytes to write.<br> rxBuf: the received data bytes.<br> count: the number of bytes to transfer.<br></code><br><br>Returns the number of bytes transferred if OK, otherwise
PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or PI_SPI_XFER_FAILED.
This function opens a serial device at a specified baud rate
with specified flags. The device name must start with
/dev/tty or /dev/serial.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> ser_tty: the serial device to open.<br> baud: the baud rate in bits per second, see below.<br>ser_flags: 0.<br></code><br><br>Returns a handle (>=0) if OK, otherwise PI_NO_HANDLE, or
PI_SER_OPEN_FAILED.
<br><br>The baud rate must be one of 50, 75, 110, 134, 150,
This function writes bVal to the serial port associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#serial_open">serial_open</a>.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This function writes count bytes from buf to the the serial port
associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#serial_open">serial_open</a>.<br> buf: the array of bytes to write.<br> count: the number of bytes to write.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
This function reads up to count bytes from the the serial port
associated with handle and writes them to buf.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#serial_open">serial_open</a>.<br> buf: an array to receive the read data.<br> count: the maximum number of bytes to read.<br></code><br><br>Returns the number of bytes read (>=0) if OK, otherwise PI_BAD_HANDLE,
PI_BAD_PARAM, PI_SER_READ_NO_DATA, or PI_SER_WRITE_FAILED.
Returns the number of bytes available to be read from the
device associated with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0, as returned by a call to <a href="#serial_open">serial_open</a>.<br></code><br><br>Returns the number of bytes of data available (>=0) if OK,
This function is available for user customisation.
<br><br>It returns a single integer value.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>arg1: >=0<br>arg2: >=0<br>argx: extra (byte) arguments<br>argc: number of extra arguments<br></code><br><br>Returns >= 0 if OK, less than 0 indicates a user defined error.
This function is available for user customisation.
<br><br>It differs from custom_1 in that it returns an array of bytes
rather than just an integer.
<br><br>The return value is an integer indicating the number of returned bytes.
<code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> arg1: >=0<br> argc: extra (byte) arguments<br> count: number of extra arguments<br>retBuf: buffer for returned data<br>retMax: maximum number of bytes to return<br></code><br><br>Returns >= 0 if OK, less than 0 indicates a user defined error.
<br><br>Note, the number of returned bytes will be retMax or less.
This function returns the pad drive strength in mA.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>pad: 0-2, the pad to get.<br></code><br><br>Returns the pad drive strength if OK, otherwise PI_BAD_PAD.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> pad: 0-2, the pad to set.<br>padStrength: 1-16 mA.<br></code><br><br>Returns 0 if OK, otherwise PI_BAD_PAD, or PI_BAD_STRENGTH.
This function uses the system call to execute a shell script
with the given string as its parameter.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> scriptName: the name of the script, only alphanumeric characters,<br> '-' and '_' are allowed in the name.<br>scriptString: the string to pass to the script.<br></code><br><br>The exit status of the system call is returned if OK, otherwise
PI_BAD_SHELL_STATUS.
<br><br>scriptName must exist in /opt/pigpio/cgi and must be executable.
<br><br>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.
<br><br>The following table gives some example returned statuses.
This function returns a handle to a file opened in a specified mode.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>file: the file to open.<br>mode: the file open mode.<br></code><br><br>Returns 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.
<br><br>File
<br><br>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.
<br><br>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.
<br><br>Where more than one entry matches a file the most specific rule
applies. If no entry matches a file then access is denied.
<br><br>Suppose /opt/pigpio/access contains the following entries
<br><br><code>/home/* n<br>/home/pi/shared/dir_1/* w<br>/home/pi/shared/dir_2/* r<br>/home/pi/shared/dir_3/* u<br>/home/pi/shared/dir_1/file.txt n<br></code><br><br>Files may be written in directory dir_1 with the exception
of file.txt.
<br><br>Files may be read in directory dir_2.
<br><br>Files may be read and written in directory dir_3.
<br><br>If a directory allows read, write, or read/write access then files may
be created in that directory.
<br><br>In an attempt to prevent risky permissions the following paths are
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>Macro</td><td>Value</td><td>Meaning</td></tr><tr><td>PI_FILE_READ</td><td>1</td><td>open file for reading</td></tr><tr><td>PI_FILE_WRITE</td><td>2</td><td>open file for writing</td></tr><tr><td>PI_FILE_RW</td><td>3</td><td>open file for reading and writing</td></tr></tbody></table><br><br>The following values may be or'd into the mode.
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>Macro</td><td>Value</td><td>Meaning</td></tr><tr><td>PI_FILE_APPEND</td><td>4</td><td>Writes append data to the end of the file</td></tr><tr><td>PI_FILE_CREATE</td><td>8</td><td>The file is created if it doesn't exist</td></tr><tr><td>PI_FILE_TRUNC</td><td>16</td><td>The file is truncated</td></tr></tbody></table><br><br>Newly created files are owned by root with permissions owner read and write.
This function reads up to count bytes from the the file
associated with handle and writes them to buf.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>handle: >=0 (as returned by <a href="#file_open">file_open</a>).<br> buf: an array to receive the read data.<br> count: the maximum number of bytes to read.<br></code><br><br>Returns the number of bytes read (>0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, PI_FILE_NOT_ROPEN, or PI_BAD_FILE_WRITE.
This function seeks to a position within the file associated
with handle.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> handle: >=0 (as returned by <a href="#file_open">file_open</a>).<br>seekOffset: the number of bytes to move. Positive offsets<br> move forward, negative offsets backwards.<br> seekFrom: one of PI_FROM_START (0), PI_FROM_CURRENT (1),<br> or PI_FROM_END (2).<br></code><br><br>Returns the new byte position within the file (>=0) if OK, otherwise PI_BAD_HANDLE, or PI_BAD_FILE_SEEK.
This function returns a list of files which match a pattern.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> fpat: file pattern to match.<br> buf: an array to receive the matching file names.<br>count: the maximum number of bytes to read.<br></code><br><br>Returns the number of returned bytes if OK, otherwise PI_NO_FILE_ACCESS,
or PI_NO_FILE_MATCH.
<br><br>The pattern must match an entry in /opt/pigpio/access. The pattern
may contain wildcards. See <a href="#file_open">file_open</a>.
<br><br>NOTE
<br><br>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
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br> edge: RISING_EDGE, FALLING_EDGE, or EITHER_EDGE.<br> f: the callback function.<br></code><br><br>The function returns a callback id if OK, otherwise pigif_bad_malloc,
pigif_duplicate_callback, or pigif_bad_callback.
<br><br>The callback is called with the GPIO, edge, and tick, whenever the
GPIO has the identified edge.
<br><br><code>Parameter Value Meaning<br><br>GPIO 0-31 The GPIO which has changed state<br><br>edge 0-2 0 = change to low (a falling edge)<br> 1 = change to high (a rising edge)<br> 2 = no level change (a watchdog timeout)<br><br>tick 32 bit The number of microseconds since boot<br> WARNING: this wraps around from<br> 4294967295 to 0 roughly every 72 minutes<br></code><br><br>The GPIO are sampled at a rate set when the pigpio daemon
is started (default 5 us).
<br><br>The number of samples per second is given in the following table.
<br><br><code> samples<br> per sec<br><br> 1 1,000,000<br> 2 500,000<br>sample 4 250,000<br>rate 5 200,000<br>(us) 8 125,000<br> 10 100,000<br></code><br><br>GPIO level changes shorter than the sample rate may be missed.
<br><br>The daemon software which generates the callbacks is triggered
1000 times per second. The callbacks will be called once per
level change since the last time they were called.
i.e. The callbacks will get all level changes but there will
be a latency.
<br><br>If you want to track the level of more than one GPIO do so by
maintaining the state in the callback. Do not use <a href="#gpio_read">gpio_read</a>.
Remember the event that triggered the callback may have
happened several milliseconds before and the GPIO may have
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br> edge: RISING_EDGE, FALLING_EDGE, or EITHER_EDGE.<br> f: the callback function.<br> userdata: a pointer to arbitrary user data.<br></code><br><br>The function returns a callback id if OK, otherwise pigif_bad_malloc,
pigif_duplicate_callback, or pigif_bad_callback.
<br><br>The callback is called with the GPIO, edge, tick, and the userdata
pointer, whenever the GPIO has the identified edge.
This function cancels a callback identified by its id.
<br><br><code>callback_id: >=0, as returned by a call to <a href="#callback">callback</a> or <a href="#callback_ex">callback_ex</a>.<br></code><br><br>The function returns 0 if OK, otherwise pigif_callback_not_found.
This function waits for an edge on the GPIO for up to timeout
seconds.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>user_gpio: 0-31.<br> edge: RISING_EDGE, FALLING_EDGE, or EITHER_EDGE.<br> timeout: >=0.<br></code><br><br>The function returns when the edge occurs or after the timeout.
<br><br>Do not use this function for precise timing purposes,
the edge is only checked 20 times a second. Whenever
you need to know the accurate time of GPIO events use
a <a href="#callback">callback</a> function.
<br><br>The function returns 1 if the edge occurred, otherwise 0.
This function provides a low-level interface to the SPI/I2C Slave
peripheral on the BCM chip.
<br><br>This peripheral allows the Pi to act as a hardware slave device
on an I2C or SPI bus.
<br><br>This is not a bit bang version and as such is OS timing
independent. The bus timing is handled directly by the chip.
<br><br>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.
<br><br>I can't get SPI to work properly. I tried with a
control word of 0x303 and swapped MISO and MOSI.
<br><br>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.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>bscxfer: a structure defining the transfer.<br><br>typedef struct<br>{<br> uint32_t control; // Write<br> int rxCnt; // Read only<br> char rxBuf[BSC_FIFO_SIZE]; // Read only<br> int txCnt; // Write<br> char txBuf[BSC_FIFO_SIZE]; // Write<br>} bsc_xfer_t;<br></code><br><br>To 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.
<br><br>Upon return rxCnt will be set to the number of received bytes placed
in rxBuf.
<br><br>The returned function value is the status of the transfer (see below).
<br><br>If there was an error the status will be less than zero
(and will contain the error code).
<br><br>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).
<br><br>Note that the control word sets the BSC mode. The BSC will stay in
that mode until a different control word is sent.
<br><br>GPIO used for models other than those based on the BCM2711.
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td></td><td>SDA</td><td>SCL</td><td>MOSI</td><td>SCLK</td><td>MISO</td><td>CE</td></tr><tr><td>I2C</td><td>18</td><td>19</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>SPI</td><td>-</td><td>-</td><td>18</td><td>19</td><td>20</td><td>21</td></tr></tbody></table><br><br>GPIO used for models based on the BCM2711 (e.g. the Pi4B).
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td></td><td>SDA</td><td>SCL</td><td>MOSI</td><td>SCLK</td><td>MISO</td><td>CE</td></tr><tr><td>I2C</td><td>10</td><td>11</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>SPI</td><td>-</td><td>-</td><td>10</td><td>11</td><td>9</td><td>8</td></tr></tbody></table><br><br>When a zero control word is received the used GPIO will be reset
to INPUT mode.
<br><br>control consists of the following bits.
<br><br><code>22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0<br> a a a a a a a - - IT HC TF IR RE TE BK EC ES PL PH I2 SP EN<br></code><br><br>Bits 0-13 are copied unchanged to the BSC CR register. See
pages 163-165 of the Broadcom peripherals document for full
details.
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>aaaaaaa</td><td>defines the I2C slave address (only relevant in I2C mode)</td></tr><tr><td>IT</td><td>invert transmit status flags</td></tr><tr><td>HC</td><td>enable host control</td></tr><tr><td>TF</td><td>enable test FIFO</td></tr><tr><td>IR</td><td>invert receive status flags</td></tr><tr><td>RE</td><td>enable receive</td></tr><tr><td>TE</td><td>enable transmit</td></tr><tr><td>BK</td><td>abort operation and clear FIFOs</td></tr><tr><td>EC</td><td>send control register as first I2C byte</td></tr><tr><td>ES</td><td>send status register as first I2C byte</td></tr><tr><td>PL</td><td>set SPI polarity high</td></tr><tr><td>PH</td><td>set SPI phase high</td></tr><tr><td>I2</td><td>enable I2C mode</td></tr><tr><td>SP</td><td>enable SPI mode</td></tr><tr><td>EN</td><td>enable BSC peripheral</td></tr></tbody></table><br><br>The returned status has the following format
<br><br><code>20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0<br> S S S S S R R R R R T T T T T RB TE RF TF RE TB<br></code><br><br>Bits 0-15 are copied unchanged from the BSC FR register. See
pages 165-166 of the Broadcom peripherals document for full
details.
<br><br><table border="1" cellpadding="2" cellspacing="2"><tbody><tr><td>SSSSS</td><td>number of bytes successfully copied to transmit FIFO</td></tr><tr><td>RRRRR</td><td>number of bytes in receieve FIFO</td></tr><tr><td>TTTTT</td><td>number of bytes in transmit FIFO</td></tr><tr><td>RB</td><td>receive busy</td></tr><tr><td>TE</td><td>transmit FIFO empty</td></tr><tr><td>RF</td><td>receive FIFO full</td></tr><tr><td>TF</td><td>transmit FIFO full</td></tr><tr><td>RE</td><td>receive FIFO empty</td></tr><tr><td>TB</td><td>transmit busy</td></tr></tbody></table><br><br>The following example shows how to configure the BSC peripheral as
an I2C slave with address 0x13 and send four bytes.
This function allows the Pi to act as a slave I2C device.
<br><br>This function is not available on the BCM2711 (e.g.as
used in the Pi4B).
<br><br>The data bytes (if any) are written to the BSC transmit
FIFO and the bytes in the BSC receive FIFO are returned.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>i2c_addr: 0-0x7F.<br> bscxfer: a structure defining the transfer.<br><br>typedef struct<br>{<br> uint32_t control; // N/A<br> int rxCnt; // Read only<br> char rxBuf[BSC_FIFO_SIZE]; // Read only<br> int txCnt; // Write<br> char txBuf[BSC_FIFO_SIZE]; // Write<br>} bsc_xfer_t;<br></code><br><br>txCnt is set to the number of bytes to be transmitted, possibly
zero. The data itself should be copied to txBuf.
<br><br>Any received data will be written to rxBuf with rxCnt set.
<br><br>See <a href="#bsc_xfer">bsc_xfer</a> for details of the returned status value.
<br><br>If there was an error the status will be less than zero
(and will contain the error code).
<br><br>Note that an i2c_address of 0 may be used to close
the BSC device and reassign the used GPIO as inputs.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br>event: 0-31.<br> f: the callback function.<br></code><br><br>The function returns a callback id if OK, otherwise pigif_bad_malloc,
pigif_duplicate_callback, or pigif_bad_callback.
<br><br>The callback is called with the event id, and tick, whenever the
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> event: 0-31.<br> f: the callback function.<br>userdata: a pointer to arbitrary user data.<br></code><br><br>The function returns a callback id if OK, otherwise pigif_bad_malloc,
pigif_duplicate_callback, or pigif_bad_callback.
<br><br>The callback is called with the event id, the tick, and the userdata
This function cancels an event callback identified by its id.
<br><br><code>callback_id: >=0, as returned by a call to <a href="#event_callback">event_callback</a> or<br><a href="#event_callback_ex">event_callback_ex</a>.<br></code><br><br>The function returns 0 if OK, otherwise pigif_callback_not_found.
This function waits for an event for up to timeout seconds.
<br><br><code> pi: >=0 (as returned by <a href="#pigpio_start">pigpio_start</a>).<br> event: 0-31.<br>timeout: >=0.<br></code><br><br>The function returns when the event occurs or after the timeout.
<br><br>The function returns 1 if the event occurred, otherwise 0.
Flags which modify an I2C open command. None are currently defined.
<h3><a name="i2c_reg">i2c_reg</a>: 0-255</h3>
A register of an I2C device.
<h3><a name="*inBuf">*inBuf</a></h3>
A buffer used to pass data to a function.
<h3><a name="inLen">inLen</a></h3>
The number of bytes of data in a buffer.
<h3><a name="int">int</a></h3>
A whole number, negative or positive.
<h3><a name="int32_t">int32_t</a></h3>
A 32-bit signed value.
<h3><a name="invert">invert</a></h3>
A flag used to set normal or inverted bit bang serial data level logic.
<h3><a name="level">level</a></h3>
The level of a GPIO. Low or High.
<br><br><code>PI_OFF 0<br>PI_ON 1<br><br>PI_CLEAR 0<br>PI_SET 1<br><br>PI_LOW 0<br>PI_HIGH 1<br></code><br><br>There is one exception. If a watchdog expires on a GPIO the level will be
reported as PI_TIMEOUT. See <a href="#set_watchdog">set_watchdog</a>.
The GPIO used for the MISO signal when bit banging SPI.
<h3><a name="mode">mode</a></h3>
1. The operational mode of a GPIO, normally INPUT or OUTPUT.
<br><br><code>PI_INPUT 0<br>PI_OUTPUT 1<br>PI_ALT0 4<br>PI_ALT1 5<br>PI_ALT2 6<br>PI_ALT3 7<br>PI_ALT4 3<br>PI_ALT5 2<br></code><br><br>2. The mode of waveform transmission.
<br><br><code>PI_WAVE_MODE_ONE_SHOT 0<br>PI_WAVE_MODE_REPEAT 1<br>PI_WAVE_MODE_ONE_SHOT_SYNC 2<br>PI_WAVE_MODE_REPEAT_SYNC 3<br></code><br><br>3. A file open mode.
<br><br><code>PI_FILE_READ 1<br>PI_FILE_WRITE 2<br>PI_FILE_RW 3<br></code><br><br>The following values can be or'd into the mode.
A pointer to arbitrary user data. This may be used to identify the instance.
<br><br>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.
<br><br>In the calling function:
<br><br><code>user_type *userdata;<br><br>user_type my_userdata;<br><br>userdata = malloc(sizeof(user_type));<br><br>*userdata = my_userdata;<br></code><br><br>In the receiving function:
