pigpio/pigpiod_if.h

/*
This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org/>
*/

#ifndef PIGPIOD_IF_H
#define PIGPIOD_IF_H

#include "pigpio.h"

#define PIGPIOD_IF_VERSION 8

/*TEXT

pigpiod_if is a C library for the Raspberry which allows control
of the gpios via the socket interface to the pigpio daemon. 

*Features*

o PWM on any of gpios 0-31

o servo pulses on any of gpios 0-31

o callbacks when any of gpios 0-31 change state

o callbacks at timed intervals

o reading/writing all of the gpios in a bank as one operation

o individually setting gpio modes, reading and writing

o notifications when any of gpios 0-31 change state

o the construction of output waveforms with microsecond timing

o rudimentary permission control over gpios

o a simple interface to start and stop new threads

o I2C, SPI, and serial link wrappers

o creating and running scripts on the pigpio daemon

*gpios*

ALL gpios are identified by their Broadcom number.

*Notes*

The PWM and servo pulses are timed using the DMA and PWM/PCM peripherals.

*Usage*

Include <pigpiod_if.h> in your source files.

Assuming your source is in prog.c use the following command to build

. .
gcc -o prog prog.c -lpigpiod_if
. .

to run make sure the pigpio daemon is running

. .
sudo pigpiod

 ./prog # sudo is not required to run programs linked to pigpiod_if
. .

For examples see x_pigpiod_if.c within the pigpio archive file.

*Notes*

All the functions which return an int return < 0 on error

TEXT*/

/*OVERVIEW

ESSENTIAL

pigpio_start               Connects to the pigpio daemon
pigpio_stop                Disconnects from the pigpio daemon

BEGINNER

set_mode                   Set a gpio mode
get_mode                   Get a gpio mode

set_pull_up_down           Set/clear gpio pull up/down resistor

gpio_read                  Read a gpio
gpio_write                 Write a gpio

set_PWM_dutycycle          Start/stop PWM pulses on a gpio

set_servo_pulsewidth       Start/stop servo pulses on a gpio

callback                   Create gpio level change callback
callback_ex                Create gpio level change callback
callback_cancel            Cancel a callback
wait_for_edge              Wait for gpio level change

INTERMEDIATE

gpio_trigger               Send a trigger pulse to a gpio.

set_watchdog               Set a watchdog on a gpio.

set_PWM_range              Configure PWM range for a gpio
get_PWM_range              Get configured PWM range for a gpio

set_PWM_frequency          Configure PWM frequency for a gpio
get_PWM_frequency          Get configured PWM frequency for a gpio

read_bank_1                Read all gpios in bank 1
read_bank_2                Read all gpios in bank 2

clear_bank_1               Clear selected gpios in bank 1
clear_bank_2               Clear selected gpios in bank 2

set_bank_1                 Set selected gpios in bank 1
set_bank_2                 Set selected gpios in bank 2

start_thread               Start a new thread
stop_thread                Stop a previously started thread

ADVANCED

get_PWM_real_range         Get underlying PWM range for a gpio

notify_open                Request a notification handle
notify_begin               Start notifications for selected gpios
notify_pause               Pause notifications
notify_close               Close a notification

bb_serial_read_open        Opens a gpio for bit bang serial reads
bb_serial_read             Reads bit bang serial data from a gpio
bb_serial_read_close       Closes a gpio for bit bang serial reads

SCRIPTS

store_script               Store a script
run_script                 Run a stored script
script_status              Get script status and parameters
stop_script                Stop a running script
delete_script              Delete a stored script

WAVES

wave_clear                 Deletes all waveforms

wave_add_new               Starts a new waveform
wave_add_generic           Adds a series of pulses to the waveform
wave_add_serial            Adds serial data to the waveform

wave_create                Creates a waveform from added data
wave_delete                Deletes one or more waveforms

wave_send_once             Transmits a waveform once
wave_send_repeat           Transmits a waveform repeatedly
wave_tx_busy               Checks to see if the waveform has ended
wave_tx_stop               Aborts the current waveform

wave_get_micros            Length in microseconds of the current waveform
wave_get_high_micros       Length of longest waveform so far
wave_get_max_micros        Absolute maximum allowed micros

wave_get_pulses            Length in pulses of the current waveform
wave_get_high_pulses       Length of longest waveform so far
wave_get_max_pulses        Absolute maximum allowed pulses

wave_get_cbs               Length in cbs of the current waveform
wave_get_high_cbs          Length of longest waveform so far
wave_get_max_cbs           Absolute maximum allowed cbs

wave_tx_start              Creates/transmits a waveform (DEPRECATED)
wave_tx_repeat             Creates/transmits a waveform repeatedly (DEPRECATED)

I2C

i2c_open                   Opens an I2C device
i2c_close                  Closes an I2C device

i2c_read_device            Reads the raw I2C device
i2c_write_device           Writes the raw I2C device

i2c_write_quick            smbus write quick
i2c_write_byte             smbus write byte
i2c_read_byte              smbus read byte
i2c_write_byte_data        smbus write byte data
i2c_write_word_data        smbus write word data
i2c_read_byte_data         smbus read byte data
i2c_read_word_data         smbus read word data
i2c_process_call           smbus process call
i2c_write_block_data       smbus write block data
i2c_read_block_data        smbus read block data
i2c_block_process_call     smbus block process call

i2c_write_i2c_block_data   smbus write I2C block data
i2c_read_i2c_block_data    smbus read I2C block data

SPI

spi_open                   Opens a SPI device
spi_close                  Closes a SPI device

spi_read                   Reads bytes from a SPI device
spi_write                  Writes bytes to a SPI device
spi_xfer                   Transfers bytes with a SPI device

SERIAL

serial_open                Opens a serial device (/dev/tty*)
serial_close               Closes a serial device

serial_write_byte          Writes a byte to a serial device
serial_read_byte           Reads a byte from a serial device
serial_write               Writes bytes to a serial device
serial_read                Reads bytes from a serial device

serial_data_available      Returns number of bytes ready to be read

UTILITIES

get_current_tick           Get current tick (microseconds)

get_hardware_revision      Get hardware revision
get_pigpio_version         Get the pigpio version
pigpiod_if_version         Get the pigpiod_if version

pigpio_error               Get a text description of an error code.

time_sleep                 Sleeps for a float number of seconds
time_time                  Float number of seconds since the epoch

OVERVIEW*/


typedef void (*CBFunc_t)  (unsigned user_gpio, unsigned level, uint32_t tick);

typedef void (*CBFuncEx_t)
   (unsigned user_gpio, unsigned level, uint32_t tick, void * user);

typedef struct callback_s callback_t;

#define RISING_EDGE  0
#define FALLING_EDGE 1
#define EITHER_EDGE  2

/*F*/
double time_time(void);
/*D
Return the current time in seconds since the Epoch.
D*/

/*F*/
void time_sleep(double seconds);
/*D
Delay execution for a given number of seconds.

. .
seconds: the number of seconds to delay.
. .
D*/

/*F*/
char *pigpio_error(int errnum);
/*D
Return a text description for an error code.

. .
errnum: the error code.
. .
D*/

/*F*/
unsigned pigpiod_if_version(void);
/*D
Return the pigpiod_if version.
D*/

/*F*/
pthread_t *start_thread(gpioThreadFunc_t thread_func, void *userdata);
/*D
Starts a new thread of execution with thread_func as the main routine.

. .
thread_func: the main function for the new thread.
   userdata: a pointer to an arbitrary argument.
. .

Returns a pointer to pthread_t if OK, otherwise NULL.

The function is passed the single argument userdata.

The thread can be cancelled by passing the pointer to pthread_t to
[*stop_thread*].
D*/

/*F*/
void stop_thread(pthread_t *pth);
/*D
Cancels the thread pointed at by pth.

. .
pth: the thread to be stopped.
. .

No value is returned.

The thread to be stopped should have been started with [*start_thread*].
D*/

/*F*/
int pigpio_start(char *addrStr, char *portStr);
/*D
Connect to the pigpio daemon.  Reserving command and
notification streams.

. .
addrStr: specifies the host or IP address of the Pi running the
         pigpio daemon.  It may be NULL in which case localhost
         is used unless overridden by the PIGPIO_ADDR environment
         variable.

portStr: specifies the port address used by the Pi running the
         pigpio daemon.  It may be NULL in which case "8888"
         is used unless overridden by the PIGPIO_PORT environment
         variable.
. .
D*/

/*F*/
void pigpio_stop(void);
/*D
Terminates the connection to the pigpio daemon and releases
resources used by the library.
D*/

/*F*/
int set_mode(unsigned gpio, unsigned mode);
/*D
Set the gpio mode.

. .
gpio: 0-53.
mode: PI_INPUT, PI_OUTPUT, PI_ALT0, _ALT1,
      PI_ALT2, PI_ALT3, PI_ALT4, PI_ALT5.
. .

Returns 0 if OK, otherwise PI_BAD_GPIO, PI_BAD_MODE,
or PI_NOT_PERMITTED.
D*/

/*F*/
int get_mode(unsigned gpio);
/*D
Get the gpio mode.

. .
gpio: 0-53.
. .

Returns the gpio mode if OK, otherwise PI_BAD_GPIO.
D*/

/*F*/
int set_pull_up_down(unsigned gpio, unsigned pud);
/*D
Set or clear the gpio pull-up/down resistor.

. .
gpio: 0-53.
 pud: PI_PUD_UP, PI_PUD_DOWN, PI_PUD_OFF.
. .

Returns 0 if OK, otherwise PI_BAD_GPIO, PI_BAD_PUD,
or PI_NOT_PERMITTED.
D*/

/*F*/
int gpio_read(unsigned gpio);
/*D
Read the gpio level.

. .
gpio:0-53.
. .

Returns the gpio level if OK, otherwise PI_BAD_GPIO.
D*/

/*F*/
int gpio_write(unsigned gpio, unsigned level);
/*D
Write the gpio level.

. .
 gpio: 0-53.
level: 0, 1.
. .

Returns 0 if OK, otherwise PI_BAD_GPIO, PI_BAD_LEVEL,
or PI_NOT_PERMITTED.

Notes

If PWM or servo pulses are active on the gpio they are switched off.
D*/

/*F*/
int set_PWM_dutycycle(unsigned user_gpio, unsigned dutycycle);
/*D
Start (non-zero dutycycle) or stop (0) PWM pulses on the gpio.

. .
user_gpio: 0-31.
dutycycle: 0-range (range defaults to 255).
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_DUTYCYCLE,
or PI_NOT_PERMITTED.
Notes

The [*set_PWM_range*] function may be used to change the
default range of 255.
D*/

/*F*/
int set_PWM_range(unsigned user_gpio, unsigned range);
/*D
Set the range of PWM values to be used on the gpio.

. .
user_gpio: 0-31.
    range: 25-40000.
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_DUTYRANGE,
or PI_NOT_PERMITTED.

Notes

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 of the 18 available gpio frequencies is

. .
  25(#1),    50(#2),   100(#3),   125(#4),    200(#5),    250(#6),
 400(#7),   500(#8),   625(#9),   800(#10),  1000(#11),  1250(#12),
2000(#13), 2500(#14), 4000(#15), 5000(#16), 10000(#17), 20000(#18)
. .

The real value set by set_PWM_range is (dutycycle * real range) / range.
D*/

/*F*/
int get_PWM_range(unsigned user_gpio);
/*D
Get the range of PWM values being used on the gpio.

. .
user_gpio: 0-31.
. .

Returns the dutycycle range used for the gpio if OK,
otherwise PI_BAD_USER_GPIO.
D*/

/*F*/
int get_PWM_real_range(unsigned user_gpio);
/*D
Get the real underlying range of PWM values being used on the gpio.

. .
user_gpio: 0-31.
. .

Returns the real range used for the gpio if OK,
otherwise PI_BAD_USER_GPIO.
D*/

/*F*/
int set_PWM_frequency(unsigned user_gpio, unsigned frequency);
/*D
Set the frequency (in Hz) of the PWM to be used on the gpio.

. .
user_gpio: 0-31.
frequency: 0- (Hz).
. .

Returns the numerically closest frequency if OK, otherwise
PI_BAD_USER_GPIO or PI_NOT_PERMITTED.

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 C pigpio library is started.

Each gpio can be independently set to one of 18 different
PWM frequencies.

If PWM is currently active on the gpio it will be switched
off and then back on at the new frequency.

. .
1us 40000, 20000, 10000, 8000, 5000, 4000, 2500, 2000, 1600,
     1250,  1000,   800,  500,  400,  250,  200,  100,   50

2us 20000, 10000,  5000, 4000, 2500, 2000, 1250, 1000,  800,
      625,   500,   400,  250,  200,  125,  100,   50 ,  25

4us 10000,  5000,  2500, 2000, 1250, 1000,  625,  500,  400,
      313,   250,   200,  125,  100,   63,   50,   25,   13

5us  8000,  4000,  2000, 1600, 1000,  800,  500,  400,  320,
      250,   200,   160,  100  , 80,   50,   40,   20,   10

8us  5000,  2500,  1250, 1000,  625,  500,  313,  250,  200,
      156,   125,   100,   63,   50,   31,   25,   13,    6

10us 4000,  2000,  1000,  800,  500,  400,  250,  200,  160,
      125,   100,    80,   50,   40,   25,   20,   10,    5
. .
D*/

/*F*/
int get_PWM_frequency(unsigned user_gpio);
/*D
Get the frequency of PWM being used on the gpio.

. .
user_gpio: 0-31.
. .

Returns the frequency (in hertz) used for the gpio if OK,
otherwise PI_BAD_USER_GPIO.
D*/

/*F*/
int set_servo_pulsewidth(unsigned user_gpio, unsigned pulsewidth);
/*D
Start (500-2500) or stop (0) servo pulses on the gpio.

. .
 user_gpio: 0-31.
pulsewidth: 0 (off), 500 (anti-clockwise) - 2500 (clockwise).
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_PULSEWIDTH or
PI_NOT_PERMITTED.

The selected pulsewidth will continue to be transmitted until
changed by a subsequent call to set_servo_pulsewidth.

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.

You can DAMAGE a servo if you command it to move beyond its limits.

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.

. .
Update Rate (Hz)     50   100  200  400  500
1E6/Hz            20000 10000 5000 2500 2000
. .

Firstly set the desired PWM frequency using [*set_PWM_frequency*].

Then set the PWM range using [*set_PWM_range*] to 1E6/Hz.
Doing this allows you to use units of microseconds when setting
the servo pulse width.

E.g. If you want to update a servo connected to gpio 25 at 400Hz

. .
set_PWM_frequency(25, 400);
set_PWM_range(25, 2500);
. .

Thereafter use the [*set_PWM_dutycycle*] function to move the servo,
e.g. set_PWM_dutycycle(25, 1500) will set a 1500 us pulse. 
D*/

/*F*/
int notify_open(void);
/*D
Get 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.

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 [*callback*]
should be used instead.

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.
D*/

/*F*/
int notify_begin(unsigned handle, uint32_t bits);
/*D
Start notifications on a previously opened handle.

. .
handle: 0-31 (as returned by [*notify_open*])
  bits: a mask indicating the gpios to be notified.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE.

The notification sends state changes for each gpio whose
corresponding bit in bits is set.

Notes

Each notification occupies 12 bytes in the fifo as follows:

. .
H (16 bit) seqno
H (16 bit) flags
I (32 bit) tick
I (32 bit) level
. .
D*/

/*F*/
int notify_pause(unsigned handle);
/*D
Pause notifications on a previously opened handle.

. .
handle: 0-31 (as returned by [*notify_open*])
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE.

Notifications for the handle are suspended until
[*notify_begin*] is called again.
D*/

/*F*/
int notify_close(unsigned handle);
/*D
Stop notifications on a previously opened handle and
release the handle for reuse.

. .
handle: 0-31 (as returned by [*notify_open*])
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE.
D*/

/*F*/
int set_watchdog(unsigned user_gpio, unsigned timeout);
/*D
Sets a watchdog for a gpio.

. .
user_gpio: 0-31.
  timeout: 0-60000.
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO
or PI_BAD_WDOG_TIMEOUT.

The watchdog is nominally in milliseconds.

Only one watchdog may be registered per gpio.

The watchdog may be cancelled by setting timeout to 0.

If no level change has been detected for the gpio for timeout
milliseconds any notification for the gpio has a report written
to the fifo with the flags set to indicate a watchdog timeout.

The [*callback*] and [*callback_ex*] functions interpret the flags
and will call registered callbacks for the gpio with level TIMEOUT.
D*/

/*F*/
uint32_t read_bank_1(void);
/*D
Read the levels of the bank 1 gpios (gpios 0-31).

The returned 32 bit integer has a bit set if the corresponding
gpio is logic 1.  Gpio n has bit value (1<<n).
D*/

/*F*/
uint32_t read_bank_2(void);
/*D
Read the levels of the bank 2 gpios (gpios 32-53).

The returned 32 bit integer has a bit set if the corresponding
gpio is logic 1.  Gpio n has bit value (1<<(n-32)).
D*/

/*F*/
int clear_bank_1(uint32_t bits);
/*D
Clears gpios 0-31 if the corresponding bit in bits is set.

. .
bits: a bit mask with 1 set if the corresponding gpio is
      to be cleared.
. .

Returns 0 if OK, otherwise PI_SOME_PERMITTED.

A status of PI_SOME_PERMITTED indicates that the user is not
allowed to write to one or more of the gpios.
D*/

/*F*/
int clear_bank_2(uint32_t bits);
/*D
Clears gpios 32-53 if the corresponding bit (0-21) in bits is set.

. .
bits: a bit mask with 1 set if the corresponding gpio is
      to be cleared.
. .

Returns 0 if OK, otherwise PI_SOME_PERMITTED.

A status of PI_SOME_PERMITTED indicates that the user is not
allowed to write to one or more of the gpios.
D*/

/*F*/
int set_bank_1(uint32_t bits);
/*D
Sets gpios 0-31 if the corresponding bit in bits is set.

. .
bits: a bit mask with 1 set if the corresponding gpio is
      to be set.
. .

Returns 0 if OK, otherwise PI_SOME_PERMITTED.

A status of PI_SOME_PERMITTED indicates that the user is not
allowed to write to one or more of the gpios.
D*/

/*F*/
int set_bank_2(uint32_t bits);
/*D
Sets gpios 32-53 if the corresponding bit (0-21) in bits is set.

. .
bits: a bit mask with 1 set if the corresponding gpio is
      to be set.
. .

Returns 0 if OK, otherwise PI_SOME_PERMITTED.

A status of PI_SOME_PERMITTED indicates that the user is not
allowed to write to one or more of the gpios.
D*/

/*F*/
uint32_t get_current_tick(void);
/*D
Gets 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.

D*/

/*F*/
uint32_t get_hardware_revision(void);
/*D
Get the Pi's hardware revision number.

The hardware revision is the last 4 characters on the Revision line
of /proc/cpuinfo.

If the hardware revision can not be found or is not a valid
hexadecimal number the function returns 0.

The revision number can be used to determine the assignment of gpios
to pins.

There are currently three types of board.

Type 1 has gpio 0 on P1-3, gpio 1 on P1-5, and gpio 21 on P1-13.

Type 2 has gpio 2 on P1-3, gpio 3 on P1-5, gpio 27 on P1-13, and
gpios 28-31 on P5.

Type 3 has a 40 pin connector rather than the 26 pin connector of
the earlier boards. Gpios 0 to 27 are brought out to the connector.

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 number 16.
D*/

/*F*/
uint32_t get_pigpio_version(void);
/*D
Returns the pigpio version.
D*/


/*F*/
int wave_clear(void);
/*D
This function clears all waveforms and any data added by calls to the
[*wave_add_**] functions.

Returns 0 if OK.
D*/

/*F*/
int wave_add_new(void);
/*D
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 [*wave_create*] function.

Returns 0 if OK.
D*/

/*F*/
int wave_add_generic(unsigned numPulses, gpioPulse_t *pulses);
/*D
This function adds a number of pulses to the current waveform.

. .
numPulses: the number of pulses.
   pulses: an array of pulses.
. .

Returns 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 solely of a delay.
D*/

/*F*/
int wave_add_serial
   (unsigned user_gpio, unsigned bbBaud, unsigned offset,
    unsigned numChar, char *str);
/*D
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: 0-31.
   bbBaud: 100-250000
   offset: 0-
  numChar: 1-
      str: an array of chars.
. .

Returns the new total number of pulses in the current waveform if OK,
otherwise PI_BAD_USER_GPIO, PI_BAD_WAVE_BAUD, PI_TOO_MANY_CHARS, or
PI_TOO_MANY_PULSES.

NOTES:

The serial data is formatted as one start bit, eight data bits, and one
stop bit.

It is legal to add serial data streams with different baud rates to
the same waveform.
D*/

/*F*/
int wave_create(void);
/*D
This function creates a waveform from the data provided by the prior
calls to the [*wave_add_**] functions.  Upon success a positive wave id
is returned.

The data provided by the [*wave_add_**] functions is consumed by this
function.

As many waveforms may be created as there is space available.  The
wave id is passed to [*wave_send_**] to specify the waveform to transmit.

Normal usage would be

Step 1. [*wave_clear*] to clear all waveforms and added data.

Step 2. [*wave_add_**] calls to supply the waveform data.

Step 3. [*wave_create*] to create the waveform and get a unique id

Repeat steps 2 and 3 as needed.

Step 4. [*wave_send_**] with the id of the waveform to transmit.

A waveform comprises one or more pulses.  Each pulse consists of a
[*gpioPulse_t*] structure.

. .
typedef struct
{
   uint32_t gpioOn;
   uint32_t gpioOff;
   uint32_t usDelay;
} gpioPulse_t;
. .

The fields specify

1) the gpios to be switched on at the start of the pulse. 
2) the gpios 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.
D*/


/*F*/
int wave_delete(unsigned wave_id);
/*D
This function deletes all created waveforms with ids greater than or
equal to wave_id.

. .
wave_id: >=0, as returned by [*wave_create*].
. .

Wave ids are allocated in order, 0, 1, 2, etc.

Returns 0 if OK, otherwise PI_BAD_WAVE_ID.
D*/

/*F*/
int wave_tx_start(void);
/*D
This function is deprecated and should no longer be used.  Use
[*wave_create*]/[*wave_send_**] instead.
D*/

/*F*/
int wave_tx_repeat(void);
/*D
This function is deprecated and should no longer be used.  Use
[*wave_create*]/[*wave_send_**] instead.
D*/

/*F*/
int wave_send_once(unsigned wave_id);
/*D
This function transmits the waveform with id wave_id.  The waveform
is sent once.

. .
wave_id: >=0, as returned by [*wave_create*].
. .

Returns the number of DMA control blocks in the waveform if OK,
otherwise PI_BAD_WAVE_ID, or PI_BAD_WAVE_MODE.
D*/

/*F*/
int wave_send_repeat(unsigned wave_id);
/*D
This function transmits the waveform with id wave_id.  The waveform
cycles until cancelled (either by the sending of a new waveform or
by [*wave_tx_stop*]).

. .
wave_id: >=0, as returned by [*wave_create*].
. .

Returns the number of DMA control blocks in the waveform if OK,
otherwise PI_BAD_WAVE_ID, or PI_BAD_WAVE_MODE.
D*/


/*F*/
int wave_tx_busy(void);
/*D
This function checks to see if a waveform is currently being
transmitted.

Returns 1 if a waveform is currently being transmitted, otherwise 0.
D*/

/*F*/
int wave_tx_stop(void);
/*D
This function stops the transmission of the current waveform.

Returns 0 if OK.

This function is intended to stop a waveform started with the repeat mode.
D*/

/*F*/
int wave_get_micros(void);
/*D
This function returns the length in microseconds of the current
waveform.
D*/

/*F*/
int wave_get_high_micros(void);
/*D
This function returns the length in microseconds of the longest waveform
created since the pigpio daemon was started.
D*/

/*F*/
int wave_get_max_micros(void);
/*D
This function returns the maximum possible size of a waveform in 
microseconds.
D*/

/*F*/
int wave_get_pulses(void);
/*D
This function returns the length in pulses of the current waveform.
D*/

/*F*/
int wave_get_high_pulses(void);
/*D
This function returns the length in pulses of the longest waveform
created since the pigpio daemon was started.
D*/

/*F*/
int wave_get_max_pulses(void);
/*D
This function returns the maximum possible size of a waveform in pulses.
D*/

/*F*/
int wave_get_cbs(void);
/*D
This function returns the length in DMA control blocks of the current
waveform.
D*/

/*F*/
int wave_get_high_cbs(void);
/*D
This function returns the length in DMA control blocks of the longest
waveform created since the pigpio daemon was started.
D*/

/*F*/
int wave_get_max_cbs(void);
/*D
This function returns the maximum possible size of a waveform in DMA
control blocks.
D*/

/*F*/
int gpio_trigger(unsigned user_gpio, unsigned pulseLen, unsigned level);
/*D
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: 0-31.
 pulseLen: 1-50.
    level: 0,1.
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_LEVEL,
PI_BAD_PULSELEN, or PI_NOT_PERMITTED.
D*/

/*F*/
int store_script(char *script);
/*D
This function stores a script for later execution.

. .
script: the text of the script.
. .

The function returns a script id if the script is valid,
otherwise PI_BAD_SCRIPT.
D*/

/*F*/
int run_script(unsigned script_id, unsigned numPar, uint32_t *param);
/*D
This function runs a stored script.

. .
script_id: >=0, as returned by [*store_script*].
   numPar: 0-10, the number of parameters.
    param: an array of parameters.
. .

The 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.
D*/

/*F*/
int script_status(unsigned script_id, uint32_t *param);
/*D
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 [*store_script*].
    param: an array to hold the returned 10 parameters.
. .

The function returns greater than or equal to 0 if OK,
otherwise PI_BAD_SCRIPT_ID.

The run status may be

. .
PI_SCRIPT_INITING
PI_SCRIPT_HALTED
PI_SCRIPT_RUNNING
PI_SCRIPT_WAITING
PI_SCRIPT_FAILED
. .

The current value of script parameters 0 to 9 are returned in param.
D*/

/*F*/
int stop_script(unsigned script_id);
/*D
This function stops a running script.

. .
script_id: >=0, as returned by [*store_script*].
. .

The function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID.
D*/

/*F*/
int delete_script(unsigned script_id);
/*D
This function deletes a stored script.

. .
script_id: >=0, as returned by [*store_script*].
. .

The function returns 0 if OK, otherwise PI_BAD_SCRIPT_ID.
D*/

/*F*/
int bb_serial_read_open(unsigned user_gpio, unsigned bbBaud);
/*D
This function opens a gpio for bit bang reading of serial data.

. .
user_gpio: 0-31.
   bbBaud: 100-250000
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO, PI_BAD_WAVE_BAUD,
or PI_GPIO_IN_USE.

The serial data is returned in a cyclic buffer and is read using
bb_serial_read.

It is the caller's responsibility to read data from the cyclic buffer
in a timely fashion.
D*/

/*F*/
int bb_serial_read(unsigned user_gpio, void *buf, size_t bufSize);
/*D
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 [*bb_serial_read_open*].
      buf: an array to receive the read bytes.
  bufSize: 0-
. .

Returns the number of bytes copied if OK, otherwise PI_BAD_USER_GPIO
or PI_NOT_SERIAL_GPIO.
D*/

/*F*/
int bb_serial_read_close(unsigned user_gpio);
/*D
This function closes a gpio for bit bang reading of serial data.

. .
user_gpio: 0-31, previously opened with [*bb_serial_read_open*].
. .

Returns 0 if OK, otherwise PI_BAD_USER_GPIO, or PI_NOT_SERIAL_GPIO.
D*/

/*F*/
int i2c_open(unsigned i2c_bus, unsigned i2c_addr, unsigned i2c_flags);
/*D
This returns a handle for the device at address i2c_addr on bus i2c_bus.

. .
  i2c_bus: 0-1.
 i2c_addr: 0x08-0x77.
i2c_flags: 0.
. .

No flags are currently defined.  This parameter should be set to zero.

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.
D*/

/*F*/
int i2c_close(unsigned handle);
/*D
This closes the I2C device associated with the handle.

. .
handle: >=0, as returned by a call to [*i2c_open*].
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE.
D*/

/*F*/
int i2c_read_device(unsigned handle, char *buf, unsigned count);
/*D
This reads count bytes from the raw device into buf.

. .
handle: >=0, as returned by a call to [*i2c_open*].
   buf: an array to receive the read data bytes.
 count: >0, the number of bytes to read.
. .

Returns count (>0) if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_READ_FAILED.
D*/

/*F*/
int i2c_write_device(unsigned handle, char *buf, unsigned count);
/*D
This writes count bytes from buf to the raw device.

. .
handle: >=0, as returned by a call to [*i2c_open*].
   buf: an array containing the data bytes to write.
 count: >0, the number of bytes to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.
D*/

/*F*/
int i2c_write_quick(unsigned handle, unsigned bit);
/*D
This sends a single bit (in the Rd/Wr bit) to the device associated
with handle.

. .
handle: >=0, as returned by a call to [*i2c_open*].
   bit: 0-1, the value to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.

Quick command. smbus 2.0 5.5.1
D*/

/*F*/
int i2c_write_byte(unsigned handle, unsigned bVal);
/*D
This sends a single byte to the device associated with handle.

. .
handle: >=0, as returned by a call to [*i2c_open*].
  bVal: 0-0xFF, the value to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.

Send byte. smbus 2.0 5.5.2
D*/

/*F*/
int i2c_read_byte(unsigned handle);
/*D
This reads a single byte from the device associated with handle.

. .
handle: >=0, as returned by a call to [*i2c_open*].
. .

Returns the byte read (>=0) if OK, otherwise PI_BAD_HANDLE,
or PI_I2C_READ_FAILED.

Receive byte. smbus 2.0 5.5.3
D*/

/*F*/
int i2c_write_byte_data(unsigned handle, unsigned i2c_reg, unsigned bVal);
/*D
This writes a single byte to the specified register of the device
associated with handle.

. .
 handle: >=0, as returned by a call to [*i2c_open*].
i2c_reg: 0-255, the register to write.
   bVal: 0-0xFF, the value to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.

Write byte. smbus 2.0 5.5.4
D*/

/*F*/
int i2c_write_word_data(unsigned handle, unsigned i2c_reg, unsigned wVal);
/*D
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 [*i2c_open*].
i2c_reg: 0-255, the register to write.
   wVal: 0-0xFFFF, the value to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.

Write word. smbus 2.0 5.5.4
D*/

/*F*/
int i2c_read_byte_data(unsigned handle, unsigned i2c_reg);
/*D
This reads a single byte from the specified register of the device
associated with handle.

. .
 handle: >=0, as returned by a call to [*i2c_open*].
i2c_reg: 0-255, the register to read.
. .

Returns 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
D*/

/*F*/
int i2c_read_word_data(unsigned handle, unsigned i2c_reg);
/*D
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 [*i2c_open*].
i2c_reg: 0-255, the register to read.
. .

Returns 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
D*/

/*F*/
int i2c_process_call(unsigned handle, unsigned i2c_reg, unsigned wVal);
/*D
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.

. .
 handle: >=0, as returned by a call to [*i2c_open*].
i2c_reg: 0-255, the register to write/read.
   wVal: 0-0xFFFF, the value to write.
. .

Returns 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
D*/

/*F*/
int i2c_write_block_data(
unsigned handle, unsigned i2c_reg, char *buf, unsigned count);
/*D
This writes up to 32 bytes to the specified register of the device
associated with handle.

. .
 handle: >=0, as returned by a call to [*i2c_open*].
i2c_reg: 0-255, the register to write.
    buf: an array with the data to send.
  count: 1-32, the number of bytes to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.

Block write. smbus 2.0 5.5.7
D*/

/*F*/
int i2c_read_block_data(unsigned handle, unsigned i2c_reg, char *buf);
/*D
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 [*i2c_open*].
i2c_reg: 0-255, the register to read.
    buf: an array to receive the read data.
. .

The 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
D*/

/*F*/
int i2c_block_process_call(
unsigned handle, unsigned i2c_reg, char *buf, unsigned count);
/*D
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 [*i2c_open*].
i2c_reg: 0-255, the register to write/read.
    buf: an array with the data to send and to receive the read data.
  count: 1-32, the number of bytes to write.
. .


Returns 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
D*/

/*F*/
int i2c_read_i2c_block_data(
unsigned handle, unsigned i2c_reg, char *buf, unsigned count);
/*D
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 [*i2c_open*].
i2c_reg: 0-255, the register to read.
    buf: an array to receive the read data.
  count: 1-32, the number of bytes to read.
. .

Returns the number of bytes read (>0) if OK, otherwise PI_BAD_HANDLE,
PI_BAD_PARAM, or PI_I2C_READ_FAILED.
D*/


/*F*/
int i2c_write_i2c_block_data(
unsigned handle, unsigned i2c_reg, char *buf, unsigned count);
/*D
This writes 1 to 32 bytes to the specified register of the device
associated with handle.

. .
 handle: >=0, as returned by a call to [*i2c_open*].
i2c_reg: 0-255, the register to write.
    buf: the data to write.
  count: 1-32, the number of bytes to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_I2C_WRITE_FAILED.
D*/

/*F*/
int spi_open(unsigned spi_channel, unsigned spi_baud, unsigned spi_flags);
/*D
This function returns a handle for the SPI device on 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.

. .
spi_channel: 0-1.
   spi_baud: >1.
  spi_flags: see below.
. .

Returns a handle (>=0) if OK, otherwise PI_BAD_SPI_CHANNEL,
PI_BAD_SPI_SPEED, PI_BAD_FLAGS, or PI_SPI_OPEN_FAILED.

spiFlags consists of the least significant 8 bits.

. .
7 6 5 4 3 2 1 0
n n n n W P m m
. .

mm defines the SPI mode.

. .
Mode POL PHA
 0    0   0
 1    0   1
 2    1   0
 3    1   1
. .

P is 0 for active low chip select (normal) and 1 for active high.

W is 0 if the device is not 3-wire, 1 if the device is 3-wire.

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.

The other bits in flags should be set to zero.
D*/

/*F*/
int spi_close(unsigned handle);
/*D
This functions closes the SPI device identified by the handle.

. .
handle: >=0, as returned by a call to [*spi_open*].
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE.
D*/

/*F*/
int spi_read(unsigned handle, char *buf, unsigned count);
/*D
This function reads count bytes of data from the SPI
device associated with the handle.

. .
handle: >=0, as returned by a call to [*spi_open*].
   buf: an array to receive the read data bytes.
 count: the number of bytes to read.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or
PI_SPI_XFER_FAILED.
D*/

/*F*/
int spi_write(unsigned handle, char *buf, unsigned count);
/*D
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 [*spi_open*].
   buf: the data bytes to write.
 count: the number of bytes to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or
PI_SPI_XFER_FAILED.
D*/

/*F*/
int spi_xfer(unsigned handle, char *txBuf, char *rxBuf, unsigned count);
/*D
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 [*spi_open*].
 txBuf: the data bytes to write.
 rxBuf: the received data bytes.
 count: the number of bytes to transfer.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_SPI_COUNT, or
PI_SPI_XFER_FAILED.
D*/

/*F*/
int serial_open(char *ser_tty, unsigned ser_baud, unsigned ser_flags);
/*D
This function opens a serial device at a specified baud rate
with specified flags.

. .
  ser_tty: the serial device to open, /dev/tty*.
 ser_baud: the baud rate to use.
ser_flags: 0.
. .

Returns a handle (>=0) if OK, otherwise PI_NO_HANDLE, or
PI_SER_OPEN_FAILED.

No flags are currently defined.  This parameter should be set to zero.
D*/

/*F*/
int serial_close(unsigned handle);
/*D
This function closes the serial device associated with handle.

. .
handle: >=0, as returned by a call to [*serial_open*].
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE.
D*/

/*F*/
int serial_write_byte(unsigned handle, unsigned bVal);
/*D
This function writes bVal to the serial port associated with handle.

. .
handle: >=0, as returned by a call to [*serial_open*].
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_SER_WRITE_FAILED.
D*/

/*F*/
int serial_read_byte(unsigned handle);
/*D
This function reads a byte from the serial port associated with handle.

. .
handle: >=0, as returned by a call to [*serial_open*].
. .

Returns the read byte (>=0) if OK, otherwise PI_BAD_HANDLE,
PI_SER_READ_NO_DATA, or PI_SER_READ_FAILED.
D*/

/*F*/
int serial_write(unsigned handle, char *buf, unsigned count);
/*D
This function writes count bytes from buf to the the serial port
associated with handle.

. .
handle: >=0, as returned by a call to [*serial_open*].
   buf: the array of bytes to write.
 count: the number of bytes to write.
. .

Returns 0 if OK, otherwise PI_BAD_HANDLE, PI_BAD_PARAM, or
PI_SER_WRITE_FAILED.
D*/

/*F*/
int serial_read(unsigned handle, char *buf, unsigned count);
/*D
This function reads up to count bytes from the the serial port
associated with handle and writes them to buf.

. .
handle: >=0, as returned by a call to [*serial_open*].
   buf: an array to receive the read data.
 count: the maximum number of bytes to read.
. .

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.
D*/

/*F*/
int serial_data_available(unsigned handle);
/*D
Returns the number of bytes available to be read from the
device associated with handle.

. .
handle: >=0, as returned by a call to [*serial_open*].
. .

Returns the number of bytes of data available (>=0) if OK,
otherwise PI_BAD_HANDLE.
D*/

/*F*/
int callback(unsigned user_gpio, unsigned edge, CBFunc_t f);
/*D
This function initialises a new callback.

. .
user_gpio: 0-31.
     edge: RISING_EDGE, FALLING_EDGE, or EITHER_EDGE.
        f: the callback function.
. .

The function returns a callback id if OK, otherwise pigif_bad_malloc,
pigif_duplicate_callback, or pigif_bad_callback.

The callback is called with the gpio, edge, and tick, whenever the
gpio has the identified edge.
D*/

/*F*/
int callback_ex
   (unsigned user_gpio, unsigned edge, CBFuncEx_t f, void *userdata);
/*D
This function initialises a new callback.

. .
user_gpio: 0-31.
     edge: RISING_EDGE, FALLING_EDGE, or EITHER_EDGE.
        f: the callback function.
 userdata: a pointer to arbitrary user data.
. .

The function returns a callback id if OK, otherwise pigif_bad_malloc,
pigif_duplicate_callback, or pigif_bad_callback.

The callback is called with the gpio, edge, tick, and user, whenever
the gpio has the identified edge.

D*/

/*F*/
int callback_cancel(unsigned callback_id);
/*D
This function fim
cancels a callback identified by its id.

. .
callback_id: >=0, as returned by a call to [*callback*] or [*callback_ex*].
. .

The function returns 0 if OK, otherwise pigif_callback_not_found.
D*/

/*F*/
int wait_for_edge(unsigned user_gpio, unsigned edge, double timeout);
/*D
This function waits for edge on the gpio for up to timeout
seconds.

. .
user_gpio: 0-31.
     edge: RISING_EDGE, FALLING_EDGE, or EITHER_EDGE.
  timeout: >=0.
. .

The function returns 1 if the edge occurred, otherwise 0.

The function returns when the edge occurs or after the timeout.
D*/

/*PARAMS

*addrStr::
A string specifying the host or IP address of the Pi running
the pigpio daemon.  It may be NULL in which case localhost
is used unless overridden by the PIGPIO_ADDR environment
variable.

bbBaud::
The baud rate used for the transmission and reception of bit banged
serial data.

. .
PI_WAVE_MIN_BAUD 100
PI_WAVE_MAX_BAUD 250000
. .

bit::
A value of 0 or 1.

bits::
A value used to select gpios.  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).

*buf::
A buffer to hold data being sent or being received.

bufSize::
The size in bytes of a buffer.


bVal::0-255 (Hex 0x0-0xFF, Octal 0-0377)
An 8-bit byte value.

callback_id::
A >=0, as returned by a call to [*callback*] or [*callback_ex*].  This is
passed to [*callback_cancel*] to cancel the callback.

CBFunc_t::
. .
typedef void (*CBFunc_t)
   (unsigned user_gpio, unsigned level, uint32_t tick);
. .

CBFuncEx_t::
. .
typedef void (*CBFuncEx_t)
   (unsigned user_gpio, unsigned level, uint32_t tick, void * user);
. .


char::
A single character, an 8 bit quantity able to store 0-255.

count::
The number of bytes to be transferred in an I2C, SPI, or Serial
command.

double::
A floating point number.

dutycycle::0-range
A 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::
Used to identify a gpio level transition of interest.  A rising edge is
a level change from 0 to 1.  A falling edge is a level change from 1 to 0.

. .
RISING_EDGE  0
FALLING_EDGE 1
EITHER_EDGE. 2
. .

errnum::
A negative number indicating a function call failed and the nature
of the error.

f::
A function.

frequency::0-
The 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.


gpio::
A Broadcom numbered gpio, in the range 0-53.

gpioPulse_t::
. .
typedef struct
{
uint32_t gpioOn;
uint32_t gpioOff;
uint32_t usDelay;
} gpioPulse_t;
. .

gpioThreadFunc_t::
. .
typedef void *(gpioThreadFunc_t) (void *);
. .

handle::0-
A number referencing an object opened by one of [*i2c_open*], [*notify_open*],
[*serial_open*], and [*spi_open*].

i2c_addr::0x08-0x77
The address of a device on the I2C bus (0x08 - 0x77)

i2c_bus::0-1
An I2C bus, 0 or 1.

i2c_flags::0
Flags which modify an I2C open command.  None are currently defined.

i2c_reg:: 0-255
A register of an I2C device.



int::
A whole number, negative or positive.

level::
The level of a gpio.  Low or High.

. .
PI_OFF 0
PI_ON 1

PI_CLEAR 0
PI_SET 1

PI_LOW 0
PI_HIGH 1
. .

There is one exception.  If a watchdog expires on a gpio the level will be
reported as PI_TIMEOUT.  See [*set_watchdog*].

. .
PI_TIMEOUT 2
. .

mode::0-7
The operational mode of a gpio, normally INPUT or OUTPUT.

. .
PI_INPUT 0
PI_OUTPUT 1
PI_ALT0 4
PI_ALT1 5
PI_ALT2 6
PI_ALT3 7
PI_ALT4 3
PI_ALT5 2
. .

numChar::
The number of characters in a string (used when the string might contain
null characters, which would normally terminate the string).

numPar:: 0-10
The number of parameters passed to a script.

numPulses::
The number of pulses to be added to a waveform.

offset::
The associated data starts this number of microseconds from the start of
the waveform.

*param::
An array of script parameters.


*portStr::
A string specifying the port address used by the Pi running
the pigpio daemon.  It may be NULL in which case "8888"
is used unless overridden by the PIGPIO_PORT environment
variable.

*pth::
A thread identifier, returned by [*start_thread*].


pthread_t::
A thread identifier.

pud::0-2
The setting of the pull up/down resistor for a gpio, which may be off,
pull-up, or pull-down.
. .
PI_PUD_OFF 0
PI_PUD_DOWN 1
PI_PUD_UP 2
. .

pulseLen::
1-50, the length of a trigger pulse in microseconds.

*pulses::
An array of pulsed to be added to a waveform.

pulsewidth::0, 500-2500
. .
PI_SERVO_OFF 0
PI_MIN_SERVO_PULSEWIDTH 500
PI_MAX_SERVO_PULSEWIDTH 2500
. .


range::25-40000
The permissible dutycycle values are 0-range.
. .
PI_MIN_DUTYCYCLE_RANGE 25
PI_MAX_DUTYCYCLE_RANGE 40000
. .

*rxBuf::
A pointer to a buffer to receive data.

*script::
A pointer to the text of a script.

script_id::
An id of a stored script as returned by [*store_script*].


seconds::
The number of seconds.

ser_baud::
The baud rate to use on the serial link.

It must be one of 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400,
4800, 9600, 19200, 38400, 57600, 115200, 230400.

ser_flags::
Flags which modify a serial open command.  None are currently defined.

*ser_tty::
The name of a serial tty device, e.g. /dev/ttyAMA0, /dev/ttyUSB0, /dev/tty1.

size_t::
A standard type used to indicate the size of an object in bytes.

spi_baud::
The speed in bits per second to use for the SPI device.


spi_channel::
A SPI channel, 0 or 1.

spi_flags::
spi_flags consists of the least significant 8 bits.

. .
7 6 5 4 3 2 1 0
n n n n W P m m
. .

mm defines the SPI mode.

. .
Mode POL PHA
 0    0   0
 1    0   1
 2    1   0
 3    1   1
. .

P is 0 for active low chip select (normal) and 1 for active high.

W is 0 if the device is not 3-wire, 1 if the device is 3-wire.

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.

The other bits in flags should be set to zero.

*str::
 An array of characters.

thread_func::
A function of type gpioThreadFunc_t used as the main function of a
thread.

timeout::
A gpio watchdog timeout in milliseconds.
. .
PI_MIN_WDOG_TIMEOUT 0
PI_MAX_WDOG_TIMEOUT 60000
. .

*txBuf::
An array of bytes to transmit.

uint32_t::0-0-4,294,967,295 (Hex 0x0-0xFFFFFFFF)
A 32-bit unsigned value.

unsigned::
A whole number >= 0.

user_gpio::
0-31, a Broadcom numbered gpio.

*userdata::
A pointer to arbitrary user data.  This may be used to identify the instance.

void::
Denoting no parameter is required

wave_add_*::
One of [*wave_add_new*], [*wave_add_generic*], [*wave_add_serial*].

wave_id::
A number representing a waveform created by [*wave_create*].

wave_send_*::
One of [*wave_send_once*], [*wave_send_repeat*].

wVal::0-65535 (Hex 0x0-0xFFFF, Octal 0-0177777)
A 16-bit word value.

PARAMS*/

/*DEF_S pigpiod_if Error Codes*/

typedef enum
{
   pigif_bad_send           = -2000,
   pigif_bad_recv           = -2001,
   pigif_bad_getaddrinfo    = -2002,
   pigif_bad_connect        = -2003,
   pigif_bad_socket         = -2004,
   pigif_bad_noib           = -2005,
   pigif_duplicate_callback = -2006,
   pigif_bad_malloc         = -2007,
   pigif_bad_callback       = -2008,
   pigif_notify_failed      = -2009,
   pigif_callback_not_found = -2010,
} pigifError_t;

/*DEF_E*/

#endif