NAME WiringPi::API - API for wiringPi, providing access to the Raspberry Pi's board, GPIO and connected peripherals SYNOPSIS No matter which import option you choose, before you can start making calls, you must initialize the software by calling one of the setup*() routines. use WiringPi::API qw(:all) # use as a base class with OO functionality use parent 'WiringPi::API'; # use in the traditional Perl OO way use WiringPi::API; my $api = WiringPi::API->new; DESCRIPTION This is an XS-based module, and requires wiringPi version 2.36+ to be installed. The wiringPiDev shared library is also required (for the LCD functionality), but it's installed by default with wiringPi. See the documentation on the wiringPi website for a more in-depth description of most of the functions it provides. Some of the functions we've wrapped are not documented, they were just selectively plucked from the C code itself. Each mapped function lists which C function it is responsible for. EXPORT_OK Exported with the :all tag, or individually. Perl wrapper functions for the XS functions. Not all of these are direct wrappers; several have additional/modified functionality than the wrapped versions, but are still 100% compatible. setup setup_sys setup_phys setup_gpio pull_up_down read_pin write_pin pwm_write get_alt gpio_layout wpi_to_gpio phys_to_gpio pwm_set_range lcd_init lcd_home lcd_clear lcd_display lcd_cursor lcd_cursor_blink lcd_send_cmd lcd_position lcd_char_def lcd_put_char lcd_puts set_interrupt pin_mode analog_read analog_write shift_reg_setup bmp180_setup bmp180_pressure bmp180_temp ads1115_setup spi_setup spi_data phys_to_wpi serial_open serial_flush serial_put_char serial_puts serial_get_char serial_close serial_data_avail EXPORT_TAGS See EXPORT_OK :all Exports all available exportable functions. FUNCTION TABLE OF CONTENTS CORE See "CORE FUNCTIONS". BOARD See "BOARD FUNCTIONS". LCD See "LCD FUNCTIONS". INTERRUPT See "INTERRUPT FUNCTIONS". ANALOG TO DIGITAL CONVERTER See "ADC FUNCTIONS". SHIFT REGISTER See "SHIFT REGISTER FUNCTIONS" SERIAL See "SERIAL FUNCTIONS" I2C See "I2C FUNCTIONS" SPI See "SPI FUNCTIONS" BAROMETRIC SENSOR See "BMP180 PRESSURE SENSOR FUNCTIONS". CORE FUNCTIONS new() NOTE: After an object is created, one of the setup* methods must be called to initialize the Pi board. Returns a new WiringPi::API object. setup() Maps to int wiringPiSetup() Sets the pin number mapping scheme to wiringPi. See pinout.xyz for a pin number conversion chart, or on the command line, run gpio readall. Note that only one of the setup*() methods should be called per program run. setup_gpio() Maps to int wiringPiSetupGpio() Sets the pin numbering scheme to GPIO. Personally, this is the setup routine that I always use, due to the GPIO numbers physically printed right on the Pi board. setup_phys() Maps to int wiringPiSetupPhys() Sets the pin mapping to use the physical pin position number on the board. setup_sys() Maps to int wiringPiSetupSys() DEPRECATED. This function is here for legacy purposes only, to provide non-root user access to the GPIO. It required exporting the pins manually before use. wiringPi now uses /dev/gpiomem by default, which does not require root level access. Sets the pin numbering scheme to GPIO. pin_mode($pin, $mode) Maps to void pinMode(int pin, int mode) Puts the pin in either INPUT, OUTPUT, PWM or GPIO_CLOCK mode. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $mode Mandatory: 0 for INPUT, 1 OUTPUT, 2 PWM_OUTPUT and 3 GPIO_CLOCK. pin_mode_alt($pin, $alt) Maps to the undocumented void pinModeAlt(int pin, int mode) Allows you to set any pin to any mode. ALT modes allowed: value mode ------------ 0 INPUT 1 OUTPUT 4 ALT0 5 ALT1 6 ALT2 7 ALT3 3 ALT4 2 ALT5 Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $alt Mandatory, Integer: The mode you want to put the pin into. See the list above for the relevant values for this parameter. read_pin($pin); Maps to int digitalRead(int pin) Returns the current state (HIGH/on, LOW/off) of a given pin. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. write_pin($pin, $state) Maps to void digitalWrite(int pin, int state) Sets the state (HIGH/on, LOW/off) of a given pin. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $state Mandatory: 1 to turn the pin on (HIGH), and 0 to turn it LOW (off). analog_read($pin); Maps to int analogRead(int pin) Returns the data for an analog pin. Note that the Raspberry Pi doesn't have analog pins, so this is used when connected through an ADC or to pseudo analog pins. Parameters: $pin Mandatory: The pseudo pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. analog_write($pin, $value) Maps to void analogWrite(int pin, int value) Writes the value to the corresponding analog pseudo pin. Parameters: $pin Mandatory: The pseudo pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $value Mandatory: The data which you want to write to the pseudo pin. pull_up_down($pin, $direction) Maps to void pullUpDnControl(int pin, int pud) Enable/disable the built-in pull up/down resistors for a specified pin. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $direction Mandatory: 2 for UP, 1 for DOWN and 0 to disable the resistor. pwm_write($pin, $value) Maps to void pwmWrite(int pin, int value) Sets the Pulse Width Modulation duty cycle (on-time) of the pin. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $value Mandatory: 0 to 1023. 0 is 0% (off) and 1023 is 100% (fully on). get_alt($pin) Maps to int getAlt(int pin) This returns the current mode of the pin (using getAlt() C call). Modes are INPUT 0, OUTPUT 1, PWM_OUT 2 and CLOCK 3. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. BOARD FUNCTIONS gpio_layout() Maps to int piGpioLayout() Returns the Raspberry Pi board's GPIO layout (ie. the board revision). wpi_to_gpio($pin_num) Maps to int wpiPinToGpio(int pin) Converts a wiringPi pin number to the Broadcom (GPIO) representation, and returns it. Parameters: $pin_num Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. phys_to_gpio($pin_num) Maps to int physPinToGpio(int pin) Converts the pin number on the physical board to the GPIO representation, and returns it. Parameters: $pin_num Mandatory: The pin number on the physical Raspberry Pi board. phys_to_wpi($pin_num) Maps to int physPinToWpi(int pin) Converts the pin number on the physical board to the wiringPi numbering representation, and returns it. Parameters: $pin_num Mandatory: The pin number on the physical Raspberry Pi board. pwm_set_range($range); Maps to void pwmSetRange(int range) Sets the range register of the Pulse Width Modulation (PWM) functionality. It defaults to 1024 (0-1023). Parameters: $range Mandatory: An integer between 0 and 1023. LCD FUNCTIONS There are several methods to drive standard Liquid Crystal Displays. See wiringPiDev LCD page for full details. lcd_init(%args) Maps to: int lcdInit( rows, cols, bits, rs, strb, d0, d1, d2, d3, d4, d5, d6, d7 ); Initializes the LCD library, and returns an integer representing the handle (file descriptor) of the device. Parameters: %args = ( rows => $num, # number of rows. eg: 2 or 4 cols => $num, # number of columns. eg: 16 or 20 bits => 4|8, # width of the interface (4 or 8) rs => $pin_num, # pin number of the LCD's RS pin strb => $pin_num, # pin number of the LCD's strobe (E) pin d0 => $pin_num, # pin number for LCD data pin 1 ... d7 => $pin_num, # pin number for LCD data pin 8 ); Mandatory: All entries must have a value. If you're only using four (4) bit width, d4 through d7 must be set to 0. Note: When in 4-bit mode, the d0 through 3 parameters actually map to pins d4 through d7 on the LCD board, so you need to connect those pins to their respective selected GPIO pins. NOTE: There is an upper limit of the number of LCDs that can be initialized simultaneously. This number is 8 (0-7). Always check the return of this function to ensure you're under the maximum file descriptors. If you receive a `-1`, you're out of bounds, and any functions called on the LCD will cause a segmentation fault. lcd_home($fd) Maps to void lcdHome(int fd) Moves the LCD cursor to the home position (top row, leftmost column). Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). lcd_clear($fd) Maps to void lcdClear(int fd) Clears the LCD display. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). lcd_display($fd, $state) Maps to void lcdDisplay(int fd, int state) Turns the LCD display on and off. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $state Mandatory: 0 to turn the display off, and 1 for on. lcd_cursor($fd, $state) Maps to void lcdCursor(int fd, int state) Turns the LCD cursor on and off. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $state Mandatory: 0 to turn the cursor off, 1 for on. lcd_cursor_blink($fd, $state) Maps to void lcdCursorBlink(int fd, int state) Allows you to enable/disable a blinking cursor. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $state Mandatory: 0 to turn the cursor blink off, 1 for on. Default is off (0). lcd_send_cmd($fd, $command) Maps to void lcdSendCommand(int fd, char command) Sends any arbitrary command to the LCD. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $command Mandatory: A command to submit to the LCD. lcd_position($fd, $x, $y) Maps to void lcdPosition(int fd, int x, int y) Moves the cursor to the specified position on the LCD display. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $x Mandatory: Column position. 0 is the left-most edge. $y Mandatory: Row position. 0 is the top row. lcd_char_def($fd, $index, $data) Maps to void lcdCharDef(int fd, unsigned char data [8]). This function is This allows you to re-define one of the 8 user-definable characters in the display. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $index Mandatory: Index of the display character. Values are 0-7. Once the char is stored at this index, it can be used at any time with the lcd_put_char() function. $data Mandatory: Array reference of exactly 8 elements. Each element is a single unsigned char byte. These bytes represent the character from the top-line to the bottom line. Note that the characters are actually 5 x 8, so only the lower 5 bits are of each element are used (ie. `0b11111` or 0b00011111`). The index is from 0 to 7 and you can subsequently print the character defined using the lcdPutchar() call using the same index sent in to this function. lcd_put_char($fd, $char) Maps to void lcdPutChar(int fd, unsigned char data) Writes a single ASCII character to the LCD display, at the current cursor position. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $char Mandatory: The character byte to print to the LCD. Note that 0-7 are reserved for custom characters, as defined with lcd_char_def(). To print one of your custom chars, $char should be the same integer of the $index you used to store it in that function. lcd_puts($fd, $string) Maps to void lcdPuts(int fd, char *string) Writes a string to the LCD display, at the current cursor position. Parameters: $fd Mandatory: The file descriptor integer returned by lcd_init(). $string Mandatory: A string to display. INTERRUPT FUNCTIONS set_interrupt($pin, $edge, $callback) IMPORTANT: The interrupt functionality requires that your Perl can be used in pthreads. If you do not have a threaded Perl, the program will cause a segmentation fault. Wrapper around wiringPi's wiringPiISR() that allows you to send in the name of a Perl sub in your own code that will be called if an interrupt is triggered. Parameters: $pin Mandatory: The pin number, in the pin numbering scheme dictated by whichever setup*() routine you used. $edge Mandatory: 1 (lowering), 2 (raising) or 3 (both). $callback Mandatory: The string name of a subroutine previously written in your user code that will be called when the interrupt is triggered. This is your interrupt handler. ADC FUNCTIONS Analog to digital converters (ADC) allow you to read analog data on the Raspberry Pi, as the Pi doesn't have any analog input pins. This section is broken down by type/model. ADS1115 MODEL ads1115_setup($pin_base, $addr) Maps to `ads1115Setup(int pinBase, int addr)`. The ADS1115 is a four channel, 16-bit wide ADC. Parameters: $pin_base Mandatory: Signed integer, higher than that of all GPIO pins. This is the base number we'll use to access the pseudo pins on the ADC. Example: If 400 is sent in, ADC pin A0 (or 0) will be pin 400, and AD3 (the fourth analog pin) will be 403. Parameters: $addr Mandatory: Signed integer. This parameter depends on how you have the ADDR pin on the ADC connected to the Pi. Below is a chart showing if the ADDR pin is connected to the Pi Pin, you'll get the address. You can also use i2cdetect -y 1 to find out your ADC address. Pin Address --------------- Gnd 0x48 VDD 0x49 SDA 0x4A SCL 0x4B SHIFT REGISTER FUNCTIONS Shift registers allow you to add extra output pins by multiplexing a small number of GPIO. Currently, we support the SR74HC595 unit, which provides eight outputs by using only three GPIO. To further, this particular unit can be daisy chained up to four wide to provide an additional 32 outputs using the same three GPIO pins. shift_reg_setup This function configures the Raspberry Pi to use a shift register (The SR74HC595 is currently supported). Parameters: $pin_base Mandatory: Signed integer, higher than that of all existing GPIO pins. This parameter registers pin 0 on the shift register to an internal GPIO pin number. For example, setting this to 100, you will be able to access the first output on the register as GPIO 100 in all other functions. $num_pins Mandatory: Signed integer, the number of outputs on the shift register. For a single SR74HC595, this is eight. If you were to daisy chain two together, this parameter would be 16. $data_pin Mandatory: Integer, the GPIO pin number connected to the register's DS pin (14). Can be any GPIO pin capable of output. $clock_pin Mandatory: Integer, the GPIO pin number connected to the register's SHCP pin (11). Can be any GPIO pin capable of output. $latch_pin Mandatory: Integer, the GPIO pin number connected to the register's STCP pin (12). Can be any GPIO pin capable of output. SERIAL FUNCTIONS These functions provide basic access to read and write to a serial device. serial_open($device, $baud) Maps to int serialOpen(const char *device, const int baud) Opens a serial device for read/write access. Parameters: $device Mandatory, String: The name of the serial device, eg: /dev/ttyACM0. $baud Mandatory, Integer: The speed of the serial device. (eg: 9600). Return, Integer: The file descriptor of the device. serial_close($fd) Maps to void serialClose(const int fd) Closes an already open serial device. Parameters: $fd Mandatory, Integer: The file descriptor returned by your call to serial_open(). serial_flush($fd) Maps to serialFlush(const int fd) Flushes the serial device's buffer. Parameters: $fd Mandatory, Integer: The file descriptor returned by your call to serial_open(). serial_data_avail($fd) Maps to serialDataAvail(const int fd) Check if there is any data available on the serial interface. Parameters: $fd Mandatory, Integer: The file descriptor returned by your call to serial_open(). serial_get_char($fd) Maps to serialGetchar(const int fd) Read a single byte from the serial interface. Parameters: $fd Mandatory, Integer: The file descriptor returned by your call to serial_open(). serial_put_char($fd, $char) Maps to serialPutchar(const int fd, const unsigned char c) Write a single byte to the interface. Parameters: $fd Mandatory, Integer: The file descriptor returned by your call to serial_open(). $char Mandatory, Byte: A single byte to write to the serial interface. serial_puts($fd, $string) Maps to serialPuts(const int fd, const char* string) Write an arbitrary length string to the serial interface. Parameters: $fd Mandatory, Integer: The file descriptor returned by your call to serial_open(). $string Mandatory, String: The content to write to the device. I2C FUNCTIONS These functions allow you to read and write devices on the Inter-Integrated Circuit (I2C) bus. i2c_setup($addr) Maps to int wiringPiI2CSetup(int devId) Configures the I2C bus in preparation for communicating with a device. Parameters: $addr Mandatory: Integer, the address of your device as seen by running for example: i2cdetect -y 1. i2c_interface($device, $addr) Maps to iint wiringPiI2CSetupInterface(const char* device, int devId) This feature is not implemented currently, and will be used to select different I2C interfaces if the RPi ever receives them. i2c_read($fd) Performs a quick one-off, one-byte read without needing to specify the register value. Some very simple devices operate without register values needed. Parameters: $fd Mandatory: Integer, the file descriptor that was returned from i2c_setup(). Returns: A single byte of data from the device on the I2C bus. i2c_read_byte($fd, $reg) Reads a single byte from the specified register. Parameters: $fd Mandatory: Integer, the file descriptor that was returned from i2c_setup(). $reg Mandatory: Integer, the register to read data from. Returns: A single byte of data from the device on the I2C bus from the selected register. i2c_read_word($fd, $reg) Reads two bytes from the specified register. Parameters: $fd Mandatory: Integer, the file descriptor that was returned from i2c_setup(). $reg Mandatory: Integer, the register to read data from. Returns: Integer, two bytes of data from the device on the I2C bus from the selected register. i2c_write($fd, $data) Performs a quick one-off, one-byte write without needing to specify the register value. Some very simple devices operate without register values needed. Parameters: $fd Mandatory: Integer, the file descriptor that was returned from i2c_setup(). $data Mandatory: Integer, the value to write to the device. Returns: The value of the ioctl() call, 0 on success. i2c_write_byte($fd, $reg, $data) Writes a single byte to the register specified. Parameters: $fd Mandatory: Integer, the file descriptor that was returned from i2c_setup(). $reg Mandatory: Integer, the register to write the data to. $data Mandatory: Integer, the value to write to the device. Returns: The value of the ioctl() call, 0 on success. i2c_write_word($fd, $reg, $data) Writes two bytes to the register specified. Parameters: $fd Mandatory: Integer, the file descriptor that was returned from i2c_setup(). $reg Mandatory: Integer, the register to write the data to. $data Mandatory: Integer, the value to write to the device. Returns: The value of the ioctl() call, 0 on success. SPI FUNCTIONS These functions allow you to set up and read/write to devices on the serial peripheral interface (SPI) bus. spi_setup Maps to int wiringPiSPISetup(int channel, int speed) Configure the SPI bus for use to communicate with its connected devices. Parameters: $channel Mandatory: Integer, the SPI channel the device is connected to. 0 for channel /dev/spidev0.0 and 1 for channel /dev/spidev0.1. $speed Optional: Integer, the speed for SPI communication. Defaults to 1000000 (1MHz). Note that it's wise to do some error checking when attempting to open the SPI bus. We return the return value of an ioctl() call, so this does the trick: if ((spi_setup(0, 1000000) < 0){ die "failed to open the SPI bus...\n"; } spi_data Maps to: int spiDataRW(int channel, AV* data, int len), which calls int wiringPiSPIDataRW(int channel, unsigned char* data, int len). Writes, and then reads a block of data over the SPI bus. The read following the write is read into the transmit buffer, so it'll be overwritten and sent back as a Perl array. Parameters: $channel Mandatory: Integer, the SPI channel the device is connected to. 0 for channel /dev/spidev0.0 and 1 for channel /dev/spidev0.1. $data Mandatory: An array reference, with each element containing a single unsigned 8-bit byte that you want to write to the device. If you want to read-only, send in an aref with all the elements set to 0. These will be overwritten with the read data, and sent back as a Perl array. $len Mandatory: Integer, the number of bytes contained in the $data parameter array reference that will be sent to the device. I could just count the number of elements, but this keeps things consistent, and ensures the user is fully aware of the data they are sending on the bus. Returns a Perl array containing the same number of elements you sent in. # read-only... three bytes my $buf = [0x00, 0x00, 0x00]; my @ret = spiDataRW($chan, $buf, 3); BMP180 PRESSURE SENSOR FUNCTIONS These functions configure and fetch data from the BMP180 barometric pressure sensor. bmp180_setup($pin_base) Configures the system to read from a BMP180 pressure sensor. These functions can not return the raw values from the sensor. See each function documentation to learn how to do so. Parameters: $pin_base Mandatory: Integer, the number at which to place the pseudo analog pins in the GPIO stack. For example, if you use 200, pin 200 represents the temperature feature of the sensor, and 201 represents the pressure feature. Return: undef. bmp180_temp($pin, $want) Returns the temperature from the sensor. Parameters: $pin Mandatory: Integer, represents the $pin_base used in the setup function + 0. $want Optional: 'c' for Celcius, and 'f' for Farenheit. Defaults to 'f'. Return: A floating point number in the requested conversion. NOTE: To get the raw sensor temperature, call the C function bmp180Temp($pin) directly. bmp180_pressure($pin) Returns the current air pressure in kPa. Parameters: $pin Mandatory: Integer, represents the $pin_base used in the setup function + 1. Return: A floating point number that represents the air pressure in kPa. NOTE: To get the raw sensor pressure, call the C function bmp180Pressure($pin) directly. DEVELOPER FUNCTIONS These functions are under testing, or don't potentially have a use to the end user. They may be risky to use, so use at your own risk. The functions in this section do not have a Perl wrapper equivalent. pseudoPinsSetup(int pinBase) This function allocates shared memory for the pseudo pins used to communicate with devices that are beyond the reach of the Pi's GPIO (eg: shift registers, ADCs etc). Parameters: pinBase Mandatory: Integer, larger than the highest GPIO pin number. Eg: 500 will be the base for the analog pins on an ADS1115 ADC. Pin A0 would be 500, and ADC pin A3 would be 503. pinModeAlt(int pin, int mode) Undocumented function that allows any pin to be set to any mode. Parameters: pin Mandatory: Signed integer, any valid GPIO pin number. mode Mandatory: Signed integer, any valid wiringPi pin mode. digitalWriteByte(const int value) Writes an 8-bit byte to the first eight GPIO pins. Parameters: value Mandatory: Unsigned int, the byte value you want to send in. Return: void digitalWriteByte2(const int value) Same as "digitalWriteByte(const int value)", but writes to the second group of eight GPIO pins. digitalReadByte() Reads an 8-bit byte from the first eight GPIO pins on the Pi. Takes no parameters, returns the byte value as an unsigned int. digitalReadByte2() Same as "digitalReadByte", but reads from the second group of eight GPIO pins. AUTHOR Steve Bertrand, COPYRIGHT AND LICENSE Copyright (C) 2017 by Steve Bertrand This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.18.2 or, at your option, any later version of Perl 5 you may have available.