--- name: "pigpiod_if" section: "3" platform: "linux" package: "libpigpiod-if-dev" version: "1.78-1.1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/pigpiod_if" --- # pigpiod\_if(3) A C library to interface to the pigpio daemon. ## NAME pigpiod\_if - A C library to interface to the pigpio daemon. ## SYNOPSIS \#include \ gcc -Wall -pthread -o prog prog.c -lpigpiod\_if -lrt ./prog ## DESCRIPTION THIS LIBRARY IS DEPRECATED. NEW CODE SHOULD BE WRITTEN TO USE THE MORE VERSATILE pigpiod\_if2 LIBRARY. pigpiod\_if is a C library for the Raspberry which allows control of the GPIO via the socket interface to the pigpio daemon.\ ### Features o hardware timed PWM on any of GPIO 0-31 o hardware timed servo pulses on any of GPIO 0-31 o callbacks when any of GPIO 0-31 change state o callbacks at timed intervals o reading/writing all of the GPIO in a bank as one operation o individually setting GPIO modes, reading and writing o notifications when any of GPIO 0-31 change state o the construction of output waveforms with microsecond timing o rudimentary permission control over GPIO o a simple interface to start and stop new threads o I2C, SPI, and serial link wrappers o creating and running scripts on the pigpio daemon ### GPIO ALL GPIO are identified by their Broadcom number. ### Notes The PWM and servo pulses are timed using the DMA and PWM/PCM peripherals. ### Usage Include \ in your source files. Assuming your source is in prog.c use the following command to build ``` gcc -Wall -pthread -o prog prog.c -lpigpiod_if -lrt ``` 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 ## 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\ get\_PWM\_dutycycle Get the PWM dutycycle in use on a GPIO\ set\_servo\_pulsewidth Start/stop servo pulses on a GPIO\ get\_servo\_pulsewidth Get the servo pulsewidth in use 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 GPIO in bank 1\ read\_bank\_2 Read all GPIO in bank 2\ clear\_bank\_1 Clear selected GPIO in bank 1\ clear\_bank\_2 Clear selected GPIO in bank 2\ set\_bank\_1 Set selected GPIO in bank 1\ set\_bank\_2 Set selected GPIO 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 GPIO\ 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\ bb\_serial\_invert Invert serial logic (1 invert, 0 normal)\ hardware\_clock Start hardware clock on supported GPIO\ hardware\_PWM Start hardware PWM on supported GPIO\ set\_glitch\_filter Set a glitch filter on a GPIO\ set\_noise\_filter Set a noise filter on a GPIO\ ### 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\_chain Transmits a chain of waveforms\ 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\ ### I2C i2c\_open Opens an I2C device\ i2c\_close Closes an 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\ i2c\_read\_device Reads the raw I2C device\ i2c\_write\_device Writes the raw I2C device\ i2c\_zip Performs multiple I2C transactions\ bb\_i2c\_open Opens GPIO for bit banging I2C\ bb\_i2c\_close Closes GPIO for bit banging I2C\ bb\_i2c\_zip Performs multiple bit banged I2C transactions\ ### 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\ 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\ ### CUSTOM custom\_1 User custom function 1\ custom\_2 User custom function 2\ ### 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\ ## FUNCTIONS - **double time\_time(void)** - Return the current time in seconds since the Epoch. - **void time\_sleep(double seconds)** - Delay execution for a given number of seconds. ``` seconds: the number of seconds to delay. ``` - **char \*pigpio\_error(int errnum)** - Return a text description for an error code. ``` errnum: the error code. ``` - **unsigned pigpiod\_if\_version(void)** - Return the pigpiod\_if version. - **pthread\_t \*start\_thread(gpioThreadFunc\_t thread\_func, void \*userdata)** - 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**. - **void stop\_thread(pthread\_t \*pth)** - 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**. - **int pigpio\_start(char \*addrStr, char \*portStr)** - 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. ``` - **void pigpio\_stop(void)** - Terminates the connection to the pigpio daemon and releases resources used by the library. - **int set\_mode(unsigned gpio, unsigned mode)** - Set the GPIO mode. ``` gpio: 0-53. mode: PI_INPUT, PI_OUTPUT, PI_ALT0, PI_ALT1, PI_ALT2, PI_ALT3, PI_ALT4, PI_ALT5. ``` Returns 0 if OK, otherwise PI\_BAD\_GPIO, PI\_BAD\_MODE, or PI\_NOT\_PERMITTED. - **int get\_mode(unsigned gpio)** - Get the GPIO mode. ``` gpio: 0-53. ``` Returns the GPIO mode if OK, otherwise PI\_BAD\_GPIO. - **int set\_pull\_up\_down(unsigned gpio, unsigned pud)** - 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. - **int gpio\_read(unsigned gpio)** - Read the GPIO level. ``` gpio:0-53. ``` Returns the GPIO level if OK, otherwise PI\_BAD\_GPIO. - **int gpio\_write(unsigned gpio, unsigned level)** - 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. - **int set\_PWM\_dutycycle(unsigned user\_gpio, unsigned dutycycle)** - 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. - **int get\_PWM\_dutycycle(unsigned user\_gpio)** - Return the PWM dutycycle in use on a GPIO. ``` user_gpio: 0-31. ``` Returns 0 if OK, otherwise PI\_BAD\_USER\_GPIO or PI\_NOT\_PWM\_GPIO. For normal PWM the dutycycle will be out of the defined range for the GPIO (see **get\_PWM\_range**). If a hardware clock is active on the GPIO the reported dutycycle will be 500000 (500k) out of 1000000 (1M). If hardware PWM is active on the GPIO the reported dutycycle will be out of a 1000000 (1M). - **int set\_PWM\_range(unsigned user\_gpio, unsigned range)** - 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. - **int get\_PWM\_range(unsigned user\_gpio)** - 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. If a hardware clock or hardware PWM is active on the GPIO the reported range will be 1000000 (1M). - **int get\_PWM\_real\_range(unsigned user\_gpio)** - 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. If a hardware clock is active on the GPIO the reported real range will be 1000000 (1M). If hardware PWM is active on the GPIO the reported real range will be approximately 250M divided by the set PWM frequency. - **int set\_PWM\_frequency(unsigned user\_gpio, unsigned frequency)** - 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. If PWM is currently active on the GPIO it will be switched off and then back on at the new frequency. Each GPIO can be independently set to one of 18 different PWM frequencies. The selectable frequencies depend upon the sample rate which may be 1, 2, 4, 5, 8, or 10 microseconds (default 5). The sample rate is set when the pigpio daemon is started. The frequencies for each sample rate are: ``` Hertz 1: 40000 20000 10000 8000 5000 4000 2500 2000 1600 1250 1000 800 500 400 250 200 100 50 2: 20000 10000 5000 4000 2500 2000 1250 1000 800 625 500 400 250 200 125 100 50 25 4: 10000 5000 2500 2000 1250 1000 625 500 400 313 250 200 125 100 63 50 25 13 sample rate (us) 5: 8000 4000 2000 1600 1000 800 500 400 320 250 200 160 100 80 50 40 20 10 8: 5000 2500 1250 1000 625 500 313 250 200 156 125 100 63 50 31 25 13 6 10: 4000 2000 1000 800 500 400 250 200 160 125 100 80 50 40 25 20 10 5 ``` - **int get\_PWM\_frequency(unsigned user\_gpio)** - Get the frequency of PWM being used on the GPIO. ``` user_gpio: 0-31. ``` For normal PWM the frequency will be that defined for the GPIO by **set\_PWM\_frequency**. If a hardware clock is active on the GPIO the reported frequency will be that set by **hardware\_clock**. If hardware PWM is active on the GPIO the reported frequency will be that set by **hardware\_PWM**. Returns the frequency (in hertz) used for the GPIO if OK, otherwise PI\_BAD\_USER\_GPIO. - **int set\_servo\_pulsewidth(unsigned user\_gpio, unsigned pulsewidth)** - 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 pulsewidth. 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.\ - **int get\_servo\_pulsewidth(unsigned user\_gpio)** - Return the servo pulsewidth in use on a GPIO. ``` user_gpio: 0-31. ``` Returns 0 if OK, otherwise PI\_BAD\_USER\_GPIO or PI\_NOT\_SERVO\_GPIO. - **int notify\_open(void)** - 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. - **int notify\_begin(unsigned handle, uint32\_t bits)** - Start notifications on a previously opened handle. ``` handle: 0-31 (as returned by notify_open) bits: a mask indicating the GPIO 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. Each notification occupies 12 bytes in the fifo as follows: ``` typedef struct { uint16_t seqno; uint16_t flags; uint32_t tick; uint32_t level; } gpioReport_t; ``` seqno: starts at 0 each time the handle is opened and then increments by one for each report. flags: two flags are defined, PI\_NTFY\_FLAGS\_WDOG and PI\_NTFY\_FLAGS\_ALIVE. PI\_NTFY\_FLAGS\_WDOG, if bit 5 is set then bits 0-4 of the flags indicate a GPIO which has had a watchdog timeout. PI\_NTFY\_FLAGS\_ALIVE, if bit 6 is set this indicates a keep alive signal on the pipe/socket and is sent once a minute in the absence of other notification activity. tick: the number of microseconds since system boot. It wraps around after 1h12m. level: indicates the level of each GPIO. If bit 1\<\=0 numBytes: >=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\_BAD\_DATABITS, PI\_BAD\_STOP\_BITS, PI\_TOO\_MANY\_CHARS, PI\_BAD\_SER\_OFFSET, or PI\_TOO\_MANY\_PULSES. NOTES: The serial data is formatted as one start bit, **data\_bits** data bits, and **stop\_bits**/2 stop bits. It is legal to add serial data streams with different baud rates to the same waveform. **numBytes** is the number of bytes of data in str. The bytes required for each character depend upon **data\_bits**. For **data\_bits** 1-8 there will be one byte per character.\ For **data\_bits** 9-16 there will be two bytes per character.\ For **data\_bits** 17-32 there will be four bytes per character. - **int wave\_create(void)** - This function creates a waveform from the data provided by the prior calls to the **wave\_add\_\*** functions. Upon success a wave id greater than or equal to 0 is returned, otherwise PI\_EMPTY\_WAVEFORM, PI\_TOO\_MANY\_CBS, PI\_TOO\_MANY\_OOL, or PI\_NO\_WAVEFORM\_ID. The data provided by the **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 GPIO to be switched on at the start of the pulse.\ 2\) the GPIO to be switched off at the start of the pulse.\ 3\) the delay in microseconds before the next pulse.\ Any or all the fields can be zero. It doesn't make any sense to set all the fields to zero (the pulse will be ignored). When a waveform is started each pulse is executed in order with the specified delay between the pulse and the next. Returns the new waveform id if OK, otherwise PI\_EMPTY\_WAVEFORM, PI\_NO\_WAVEFORM\_ID, PI\_TOO\_MANY\_CBS, or PI\_TOO\_MANY\_OOL. - **int wave\_delete(unsigned wave\_id)** - This function deletes the waveform with id wave\_id. ``` wave_id: >=0, as returned by wave_create. ``` Wave ids are allocated in order, 0, 1, 2, etc. The wave is flagged for deletion. The resources used by the wave will only be reused when either of the following apply. \- all waves with higher numbered wave ids have been deleted or have been flagged for deletion. \- a new wave is created which uses exactly the same resources as the current wave (see the C source for gpioWaveCreate for details). Returns 0 if OK, otherwise PI\_BAD\_WAVE\_ID. - **int wave\_send\_once(unsigned wave\_id)** - This function transmits the waveform with id wave\_id. The waveform is sent once. NOTE: Any hardware PWM started by **hardware\_PWM** will be cancelled. ``` 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. - **int wave\_send\_repeat(unsigned wave\_id)** - 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**). NOTE: Any hardware PWM started by **hardware\_PWM** will be cancelled. ``` 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. - **int wave\_chain(char \*buf, unsigned bufSize)** - This function transmits a chain of waveforms. NOTE: Any hardware PWM started by **hardware\_PWM** will be cancelled. The waves to be transmitted are specified by the contents of buf which contains an ordered list of **wave\_id**s and optional command codes and related data. ``` buf: pointer to the wave_ids and optional command codes bufSize: the number of bytes in buf ``` Returns 0 if OK, otherwise PI\_CHAIN\_NESTING, PI\_CHAIN\_LOOP\_CNT, PI\_BAD\_CHAIN\_LOOP, PI\_BAD\_CHAIN\_CMD, PI\_CHAIN\_COUNTER, PI\_BAD\_CHAIN\_DELAY, PI\_CHAIN\_TOO\_BIG, or PI\_BAD\_WAVE\_ID. Each wave is transmitted in the order specified. A wave may occur multiple times per chain. A blocks of waves may be transmitted multiple times by using the loop commands. The block is bracketed by loop start and end commands. Loops may be nested. Delays between waves may be added with the delay command. The following command codes are supported: Name Cmd & Data Meaning\ Loop Start 255 0 Identify start of a wave block\ Loop Repeat 255 1 x y loop x + y\*256 times\ Delay 255 2 x y delay x + y\*256 microseconds\ Loop Forever 255 3 loop forever\ If present Loop Forever must be the last entry in the chain. The code is currently dimensioned to support a chain with roughly 600 entries and 20 loop counters. **Example**\ ``` #include #include #define WAVES 5 #define GPIO 4 int main(int argc, char *argv[]) { int i, wid[WAVES]; if (pigpio_start(0, 0)<0) return -1; set_mode(GPIO, PI_OUTPUT); for (i=0; i=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. - **int script\_status(unsigned script\_id, uint32\_t \*param)** - This function returns the run status of a stored script as well as the current values of parameters 0 to 9. ``` script_id: >=0, as returned by 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. - **int stop\_script(unsigned script\_id)** - 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. - **int delete\_script(unsigned script\_id)** - 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. - **int bb\_serial\_read\_open(unsigned user\_gpio, unsigned baud, unsigned data\_bits)** - This function opens a GPIO for bit bang reading of serial data. ``` user_gpio: 0-31. baud: 50-250000 data_bits: 1-32 ``` 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. - **int bb\_serial\_read(unsigned user\_gpio, void \*buf, size\_t bufSize)** - This function copies up to bufSize bytes of data read from the bit bang serial cyclic buffer to the buffer starting at buf. ``` user_gpio: 0-31, previously opened with 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. The bytes returned for each character depend upon the number of data bits **data\_bits** specified in the **bb\_serial\_read\_open** command. For **data\_bits** 1-8 there will be one byte per character.\ For **data\_bits** 9-16 there will be two bytes per character.\ For **data\_bits** 17-32 there will be four bytes per character. - **int bb\_serial\_read\_close(unsigned user\_gpio)** - 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. - **int bb\_serial\_invert(unsigned user\_gpio, unsigned invert)** - This function inverts serial logic for big bang serial reads. ``` user_gpio: 0-31, previously opened with bb_serial_read_open. invert: 0-1, 1 invert, 0 normal. ``` Returns 0 if OK, otherwise PI\_NOT\_SERIAL\_GPIO or PI\_BAD\_SER\_INVERT. - **int i2c\_open(unsigned i2c\_bus, unsigned i2c\_addr, unsigned i2c\_flags)** - This returns a handle for the device at address i2c\_addr on bus i2c\_bus. ``` i2c_bus: >=0. i2c_addr: 0-0x7F. i2c_flags: 0. ``` No flags are currently defined. This parameter should be set to zero. Physically buses 0 and 1 are available on the Pi. Higher numbered buses will be available if a kernel supported bus multiplexor is being used. The GPIO used are given in the following table. SDA SCL\ I2C 0 0 1\ I2C 1 2 3\ Returns a handle (\>=0) if OK, otherwise PI\_BAD\_I2C\_BUS, PI\_BAD\_I2C\_ADDR, PI\_BAD\_FLAGS, PI\_NO\_HANDLE, or PI\_I2C\_OPEN\_FAILED. For the SMBus commands the low level transactions are shown at the end of the function description. The following abbreviations are used. ``` S (1 bit) : Start bit P (1 bit) : Stop bit Rd/Wr (1 bit) : Read/Write bit. Rd equals 1, Wr equals 0. A, NA (1 bit) : Accept and not accept bit. Addr (7 bits): I2C 7 bit address. Comm (8 bits): Command byte, a data byte which often selects a register. Data (8 bits): A data byte. Count (8 bits): A data byte containing the length of a block operation. [..]: Data sent by the device. ``` - **int i2c\_close(unsigned handle)** - 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. - **int i2c\_write\_quick(unsigned handle, unsigned bit)** - This sends a single bit (in the Rd/Wr bit) to the device associated with handle. ``` handle: >=0, as returned by a call to 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 ``` S Addr Rd/Wr [A] P ``` - **int i2c\_write\_byte(unsigned handle, unsigned bVal)** - 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 ``` S Addr Wr [A] Data [A] P ``` - **int i2c\_read\_byte(unsigned handle)** - 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 ``` S Addr Rd [A] [Data] NA P ``` - **int i2c\_write\_byte\_data(unsigned handle, unsigned i2c\_reg, unsigned bVal)** - This writes a single byte to the specified register of the device associated with handle. ``` handle: >=0, as returned by a call to 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 ``` S Addr Wr [A] Comm [A] Data [A] P ``` - **int i2c\_write\_word\_data(unsigned handle, unsigned i2c\_reg, unsigned wVal)** - This writes a single 16 bit word to the specified register of the device associated with handle. ``` handle: >=0, as returned by a call to 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 ``` S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] P ``` - **int i2c\_read\_byte\_data(unsigned handle, unsigned i2c\_reg)** - 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 ``` S Addr Wr [A] Comm [A] S Addr Rd [A] [Data] NA P ``` - **int i2c\_read\_word\_data(unsigned handle, unsigned i2c\_reg)** - 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 ``` S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P ``` - **int i2c\_process\_call(unsigned handle, unsigned i2c\_reg, unsigned wVal)** - 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 ``` S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P ``` - **int i2c\_write\_block\_data(unsigned handle, unsigned i2c\_reg, char \*buf, unsigned count)** - This writes up to 32 bytes to the specified register of the device associated with handle. ``` handle: >=0, as returned by a call to 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 ``` S Addr Wr [A] Comm [A] Count [A] Data [A] Data [A] ... [A] Data [A] P ``` - **int i2c\_read\_block\_data(unsigned handle, unsigned i2c\_reg, char \*buf)** - This reads a block of up to 32 bytes from the specified register of the device associated with handle. ``` handle: >=0, as returned by a call to 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 ``` S Addr Wr [A] Comm [A] S Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P ``` - **int i2c\_block\_process\_call(unsigned handle, unsigned i2c\_reg, char \*buf, unsigned count)** - This writes data bytes to the specified register of the device associated with handle and reads a device specified number of bytes of data in return. ``` handle: >=0, as returned by a call to 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 ``` S Addr Wr [A] Comm [A] Count [A] Data [A] ... S Addr Rd [A] [Count] A [Data] ... A P ``` - **int i2c\_read\_i2c\_block\_data(unsigned handle, unsigned i2c\_reg, char \*buf, unsigned count)** - This reads count bytes from the specified register of the device associated with handle . The count may be 1-32. ``` handle: >=0, as returned by a call to 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. ``` S Addr Wr [A] Comm [A] S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P ``` - **int i2c\_write\_i2c\_block\_data(unsigned handle, unsigned i2c\_reg, char \*buf, unsigned count)** - This writes 1 to 32 bytes to the specified register of the device associated with handle. ``` handle: >=0, as returned by a call to 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. ``` S Addr Wr [A] Comm [A] Data [A] Data [A] ... [A] Data [A] P ``` - **int i2c\_read\_device(unsigned handle, char \*buf, unsigned count)** - 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. - **int i2c\_write\_device(unsigned handle, char \*buf, unsigned count)** - 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. - **int i2c\_zip(unsigned handle, char \*inBuf, unsigned inLen, char \*outBuf, unsigned outLen)** - This function executes a sequence of I2C operations. The operations to be performed are specified by the contents of inBuf which contains the concatenated command codes and associated data. ``` handle: >=0, as returned by a call to i2cOpen inBuf: pointer to the concatenated I2C commands, see below inLen: size of command buffer outBuf: pointer to buffer to hold returned data outLen: size of output buffer ``` Returns \>= 0 if OK (the number of bytes read), otherwise PI\_BAD\_HANDLE, PI\_BAD\_POINTER, PI\_BAD\_I2C\_CMD, PI\_BAD\_I2C\_RLEN. PI\_BAD\_I2C\_WLEN, or PI\_BAD\_I2C\_SEG. The following command codes are supported: Name Cmd & Data Meaning\ End 0 No more commands\ Escape 1 Next P is two bytes\ On 2 Switch combined flag on\ Off 3 Switch combined flag off\ Address 4 P Set I2C address to P\ Flags 5 lsb msb Set I2C flags to lsb + (msb \<\< 8)\ Read 6 P Read P bytes of data\ Write 7 P ... Write P bytes of data\ The address, read, and write commands take a parameter P. Normally P is one byte (0-255). If the command is preceded by the Escape command then P is two bytes (0-65535, least significant byte first). The address defaults to that associated with the handle. The flags default to 0. The address and flags maintain their previous value until updated. The returned I2C data is stored in consecutive locations of outBuf. **Example**\ ``` Set address 0x53, write 0x32, read 6 bytes Set address 0x1E, write 0x03, read 6 bytes Set address 0x68, write 0x1B, read 8 bytes End 0x04 0x53 0x07 0x01 0x32 0x06 0x06 0x04 0x1E 0x07 0x01 0x03 0x06 0x06 0x04 0x68 0x07 0x01 0x1B 0x06 0x08 0x00 ``` - **int bb\_i2c\_open(unsigned SDA, unsigned SCL, unsigned baud)** - This function selects a pair of GPIO for bit banging I2C at a specified baud rate. Bit banging I2C allows for certain operations which are not possible with the standard I2C driver. o baud rates as low as 50\ o repeated starts\ o clock stretching\ o I2C on any pair of spare GPIO ``` SDA: 0-31 SCL: 0-31 baud: 50-500000 ``` Returns 0 if OK, otherwise PI\_BAD\_USER\_GPIO, PI\_BAD\_I2C\_BAUD, or PI\_GPIO\_IN\_USE. NOTE: The GPIO used for SDA and SCL must have pull-ups to 3V3 connected. As a guide the hardware pull-ups on pins 3 and 5 are 1k8 in value. - **int bb\_i2c\_close(unsigned SDA)** - This function stops bit banging I2C on a pair of GPIO previously opened with **bb\_i2c\_open**. ``` SDA: 0-31, the SDA GPIO used in a prior call to bb_i2c_open ``` Returns 0 if OK, otherwise PI\_BAD\_USER\_GPIO, or PI\_NOT\_I2C\_GPIO. - **int bb\_i2c\_zip(unsigned SDA, char \*inBuf, unsigned inLen, char \*outBuf, unsigned outLen)** - This function executes a sequence of bit banged I2C operations. The operations to be performed are specified by the contents of inBuf which contains the concatenated command codes and associated data. ``` SDA: 0-31 (as used in a prior call to bb_i2c_open) inBuf: pointer to the concatenated I2C commands, see below inLen: size of command buffer outBuf: pointer to buffer to hold returned data outLen: size of output buffer ``` Returns \>= 0 if OK (the number of bytes read), otherwise PI\_BAD\_USER\_GPIO, PI\_NOT\_I2C\_GPIO, PI\_BAD\_POINTER, PI\_BAD\_I2C\_CMD, PI\_BAD\_I2C\_RLEN, PI\_BAD\_I2C\_WLEN, PI\_I2C\_READ\_FAILED, or PI\_I2C\_WRITE\_FAILED. The following command codes are supported: Name Cmd & Data Meaning\ End 0 No more commands\ Escape 1 Next P is two bytes\ Start 2 Start condition\ Stop 3 Stop condition\ Address 4 P Set I2C address to P\ Flags 5 lsb msb Set I2C flags to lsb + (msb \<\< 8)\ Read 6 P Read P bytes of data\ Write 7 P ... Write P bytes of data\ The address, read, and write commands take a parameter P. Normally P is one byte (0-255). If the command is preceded by the Escape command then P is two bytes (0-65535, least significant byte first). The address and flags default to 0. The address and flags maintain their previous value until updated. No flags are currently defined. The returned I2C data is stored in consecutive locations of outBuf. **Example**\ ``` Set address 0x53 start, write 0x32, (re)start, read 6 bytes, stop Set address 0x1E start, write 0x03, (re)start, read 6 bytes, stop Set address 0x68 start, write 0x1B, (re)start, read 8 bytes, stop End 0x04 0x53 0x02 0x07 0x01 0x32 0x02 0x06 0x06 0x03 0x04 0x1E 0x02 0x07 0x01 0x03 0x02 0x06 0x06 0x03 0x04 0x68 0x02 0x07 0x01 0x1B 0x02 0x06 0x08 0x03 0x00 ``` - **int spi\_open(unsigned spi\_channel, unsigned baud, unsigned spi\_flags)** - This function returns a handle for the SPI device on the channel. Data will be transferred at baud bits per second. The flags may be used to modify the default behaviour of 4-wire operation, mode 0, active low chip select. The Pi has two SPI peripherals: main and auxiliary. The main SPI has two chip selects (channels), the auxiliary has three. The auxiliary SPI is available on all models but the A and B. The GPIO used are given in the following table. MISO MOSI SCLK CE0 CE1 CE2\ Main SPI 9 10 11 8 7 -\ Aux SPI 19 20 21 18 17 16\ ``` spi_channel: 0-1 (0-2 for the auxiliary SPI). baud: 32K-125M (values above 30M are unlikely to work). spi_flags: see below. ``` 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. spi\_flags consists of the least significant 22 bits. ``` 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 b b b b b b R T n n n n W A u2 u1 u0 p2 p1 p0 m m ``` mm defines the SPI mode. Warning: modes 1 and 3 do not appear to work on the auxiliary SPI. ``` Mode POL PHA 0 0 0 1 0 1 2 1 0 3 1 1 ``` px is 0 if CEx is active low (default) and 1 for active high. ux is 0 if the CEx GPIO is reserved for SPI (default) and 1 otherwise. A is 0 for the main SPI, 1 for the auxiliary SPI. W is 0 if the device is not 3-wire, 1 if the device is 3-wire. Main SPI only. nnnn defines the number of bytes (0-15) to write before switching the MOSI line to MISO to read data. This field is ignored if W is not set. Main SPI only. T is 1 if the least significant bit is transmitted on MOSI first, the default (0) shifts the most significant bit out first. Auxiliary SPI only. R is 1 if the least significant bit is received on MISO first, the default (0) receives the most significant bit first. Auxiliary SPI only. bbbbbb defines the word size in bits (0-32). The default (0) sets 8 bits per word. Auxiliary SPI only. The **spi\_read**, **spi\_write**, and **spi\_xfer** functions transfer data packed into 1, 2, or 4 bytes according to the word size in bits. For bits 1-8 there will be one byte per word.\ For bits 9-16 there will be two bytes per word.\ For bits 17-32 there will be four bytes per word. Multi-byte transfers are made in least significant byte first order. E.g. to transfer 32 11-bit words buf should contain 64 bytes and count should be 64. E.g. to transfer the 14 bit value 0x1ABC send the bytes 0xBC followed by 0x1A. The other bits in flags should be set to zero. - **int spi\_close(unsigned handle)** - 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. - **int spi\_read(unsigned handle, char \*buf, unsigned count)** - This function reads count bytes of data from the SPI device associated with the handle. ``` handle: >=0, as returned by a call to spi_open. buf: an array to receive the read data bytes. count: the number of bytes to read. ``` Returns the number of bytes transferred if OK, otherwise PI\_BAD\_HANDLE, PI\_BAD\_SPI\_COUNT, or PI\_SPI\_XFER\_FAILED. - **int spi\_write(unsigned handle, char \*buf, unsigned count)** - This function writes count bytes of data from buf to the SPI device associated with the handle. ``` handle: >=0, as returned by a call to spi_open. buf: the data bytes to write. count: the number of bytes to write. ``` Returns the number of bytes transferred if OK, otherwise PI\_BAD\_HANDLE, PI\_BAD\_SPI\_COUNT, or PI\_SPI\_XFER\_FAILED. - **int spi\_xfer(unsigned handle, char \*txBuf, char \*rxBuf, unsigned count)** - This function transfers count bytes of data from txBuf to the SPI device associated with the handle. Simultaneously count bytes of data are read from the device and placed in rxBuf. ``` handle: >=0, as returned by a call to spi_open. txBuf: the data bytes to write. rxBuf: the received data bytes. count: the number of bytes to transfer. ``` Returns the number of bytes transferred if OK, otherwise PI\_BAD\_HANDLE, PI\_BAD\_SPI\_COUNT, or PI\_SPI\_XFER\_FAILED. - **int serial\_open(char \*ser\_tty, unsigned baud, unsigned ser\_flags)** - 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. ``` ser_tty: the serial device to open. baud: the baud rate in bits per second, see below. ser_flags: 0. ``` Returns a handle (\>=0) if OK, otherwise PI\_NO\_HANDLE, or PI\_SER\_OPEN\_FAILED. The baud rate must be one of 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, 115200, or 230400. No flags are currently defined. This parameter should be set to zero. - **int serial\_close(unsigned handle)** - 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. - **int serial\_write\_byte(unsigned handle, unsigned bVal)** - 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. - **int serial\_read\_byte(unsigned handle)** - 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. If no data is ready PI\_SER\_READ\_NO\_DATA is returned. - **int serial\_write(unsigned handle, char \*buf, unsigned count)** - This function writes count bytes from buf to the the serial port associated with handle. ``` handle: >=0, as returned by a call to 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. - **int serial\_read(unsigned handle, char \*buf, unsigned count)** - 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. If no data is ready zero is returned. - **int serial\_data\_available(unsigned handle)** - 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. - **int custom\_1(unsigned arg1, unsigned arg2, char \*argx, unsigned argc)** - This function is available for user customisation. It returns a single integer value. ``` arg1: >=0 arg2: >=0 argx: extra (byte) arguments argc: number of extra arguments ``` Returns \>= 0 if OK, less than 0 indicates a user defined error. - **int custom\_2(unsigned arg1, char \*argx, unsigned argc, char \*retBuf, unsigned retMax)** - This function is available for user customisation. It differs from custom\_1 in that it returns an array of bytes rather than just an integer. The return value is an integer indicating the number of returned bytes. ``` arg1: >=0 argc: extra (byte) arguments count: number of extra arguments retBuf: buffer for returned data retMax: maximum number of bytes to return ``` Returns \>= 0 if OK, less than 0 indicates a user defined error. Note, the number of returned bytes will be retMax or less. - **int callback(unsigned user\_gpio, unsigned edge, CBFunc\_t f)** - 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. ``` Parameter Value Meaning GPIO 0-31 The GPIO which has changed state edge 0-2 0 = change to low (a falling edge) 1 = change to high (a rising edge) 2 = no level change (a watchdog timeout) tick 32 bit The number of microseconds since boot WARNING: this wraps around from 4294967295 to 0 roughly every 72 minutes ``` - **int callback\_ex(unsigned user\_gpio, unsigned edge, CBFuncEx\_t f, void \*userdata)** - 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. ``` Parameter Value Meaning GPIO 0-31 The GPIO which has changed state edge 0-2 0 = change to low (a falling edge) 1 = change to high (a rising edge) 2 = no level change (a watchdog timeout) tick 32 bit The number of microseconds since boot WARNING: this wraps around from 4294967295 to 0 roughly every 72 minutes userdata pointer Pointer to an arbitrary object ``` - **int callback\_cancel(unsigned callback\_id)** - This function 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. - **int wait\_for\_edge(unsigned user\_gpio, unsigned edge, double timeout)** - 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. ## PARAMETERS - **active**: 0-1000000 The number of microseconds level changes are reported for once a noise filter has been triggered (by **steady** microseconds of a stable level). - **\*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. - **arg1** An unsigned argument passed to a user customised function. Its meaning is defined by the customiser. - **arg2** An unsigned argument passed to a user customised function. Its meaning is defined by the customiser. - **argc** The count of bytes passed to a user customised function. - **\*argx** A pointer to an array of bytes passed to a user customised function. Its meaning and content is defined by the customiser. - **baud** The speed of serial communication (I2C, SPI, serial link, waves) in bits per second. - **bit** A value of 0 or 1. - **bits** A value used to select GPIO. If bit n of bits is set then GPIO n is selected. A convenient way to set bit n is to or in (1\<\=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. - **clkfreq**: 4689-250000000 (250M) The hardware clock frequency. - **count** The number of bytes to be transferred in an I2C, SPI, or Serial command. - **data\_bits**: 1-32 The number of data bits in each character of serial data. ``` #define PI_MIN_WAVE_DATABITS 1 #define PI_MAX_WAVE_DATABITS 32 ``` - **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. There are 54 General Purpose Input Outputs (GPIO) named gpio0 through gpio53. They are split into two banks. Bank 1 consists of gpio0 through gpio31. Bank 2 consists of gpio32 through gpio53. All the GPIO which are safe for the user to read and write are in bank 1. Not all GPIO in bank 1 are safe though. Type 1 boards have 17 safe GPIO. Type 2 boards have 21. Type 3 boards have 26. See **get\_hardware\_revision**. The user GPIO are marked with an X in the following table. ``` 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Type 1 X X - - X - - X X X X X - - X X Type 2 - - X X X - - X X X X X - - X X Type 3 X X X X X X X X X X X X X X 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Type 1 - X X - - X X X X X - - - - - - Type 2 - X X - - - X X X X - X X X X X Type 3 X X X X X X X X X X X X - - - - ``` - **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**: 0-0x7F The address of a device on the I2C bus. - **i2c\_bus**: \>=0 An I2C bus number. - **i2c\_flags**: 0 Flags which modify an I2C open command. None are currently defined. - **i2c\_reg**: 0-255 A register of an I2C device. - **\*inBuf** A buffer used to pass data to a function. - **inLen** The number of bytes of data in a buffer. - **int** A whole number, negative or positive. - **invert** A flag used to set normal or inverted bit bang serial data level logic. - **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 ``` - **numBytes** The number of bytes used to store characters in a string. Depending on the number of bits per character there may be 1, 2, or 4 bytes per character. - **numPar**: 0-10 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. - **\*outBuf** A buffer used to return data from a function. - **outLen** The size in bytes of an output buffer. - **\*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** 1-100, the length of a trigger pulse in microseconds. - **\*pulses** An array of pulses to be added to a waveform. - **pulsewidth**: 0, 500-2500 ``` PI_SERVO_OFF 0 PI_MIN_SERVO_PULSEWIDTH 500 PI_MAX_SERVO_PULSEWIDTH 2500 ``` - **PWMduty**: 0-1000000 (1M) The hardware PWM dutycycle. ``` #define PI_HW_PWM_RANGE 1000000 ``` - **PWMfreq**: 1-125000000 (125M) The hardware PWM frequency. ``` #define PI_HW_PWM_MIN_FREQ 1 #define PI_HW_PWM_MAX_FREQ 125000000 ``` - **range**: 25-40000 The permissible dutycycle values are 0-range. ``` PI_MIN_DUTYCYCLE_RANGE 25 PI_MAX_DUTYCYCLE_RANGE 40000 ``` - **\*retBuf** A buffer to hold a number of bytes returned to a used customised function, - **retMax** The maximum number of bytes a user customised function should return. - **\*rxBuf** A pointer to a buffer to receive data. - **SCL** The user GPIO to use for the clock when bit banging I2C. - **\*script** A pointer to the text of a script. - **script\_id** An id of a stored script as returned by **store\_script**. - **SDA** The user GPIO to use for data when bit banging I2C. - **seconds** The number of seconds. - **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\_channel** A SPI channel, 0-2. - **spi\_flags** See **spi\_open**. - **steady**: 0-300000 The number of microseconds level changes must be stable for before reporting the level changed (**set\_glitch\_filter**) or triggering the active part of a noise filter (**set\_noise\_filter**). - **stop\_bits**: 2-8 The number of (half) stop bits to be used when adding serial data to a waveform. ``` #define PI_MIN_WAVE_HALFSTOPBITS 2 #define PI_MAX_WAVE_HALFSTOPBITS 8 ``` - **\*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. See **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. ## 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; ``` ## SEE ALSO pigpiod(1), [pig2vcd(1)](/pig2vcd/1.md), [pigs(1)](/pigs/1.md), pigpio(3), [pigpiod\_if2(3)](/pigpiod_if2/3.md) ## AUTHOR joan@abyz.me.uk