1 .TH "GPIO" "21st October 2012" "Command-Line access to Raspberry Pi and PiFace GPIO"
4 gpio \- Command-line access to Raspberry Pi and PiFace GPIO
12 .B read/write/wb/pwm/clock/mode ...
23 .B unexportall/exports
26 .B export/edge/unexport
54 is a swiss army knife of a command line tool to allow the user easy
55 access to the GPIO pins on the Raspberry Pi and the SPI A/D and D/A
56 converters on the Gertboard. It's designed for simple testing and
57 diagnostic purposes, but can be used in shell scripts for general if
58 somewhat slow control of the GPIO pins.
60 It can also control the IO's on the PiFace IO board and load the SPI and I2C
61 kernel modules if required.
63 Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
64 system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
65 interface without needing to be run as root.
71 Output the current version including the board revision of the Raspberry Pi.
75 Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
76 \fINOTE:\fR The BCM_GPIO pin numbers are always used with the
77 export and edge commands.
81 Use the PiFace interface board and its corresponding pin numbers.
85 Read the digital value of the given pin and print 0 or 1 to represent the
86 respective logic levels.
89 .B write <pin> <value>
90 Write the given value (0 or 1) to the pin. You need to set the pin
95 Write the given byte to the 8 main GPIO pins. You can prefix it with 0x
96 to specify a hexadecimal number. You need to set pins to output mode
101 Output a table of all GPIO pins values. The values represent the actual values read
102 if the pin is in input mode, or the last value written if the pin is in output
107 Write a PWM value (0-1023) to the given pin. The pin needs to be put
111 .B clock <pin> <frequency>
112 Set the output frequency on the given pin. The pin needs to be put into
117 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
118 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
119 pull-up, pull-down or tristate (off) controls.
123 Un-Export all the GPIO pins in the /sys/class/gpio directory.
127 Print a list (if any) of all the exported GPIO pins and their current values.
131 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
132 mode command above however only \fIin\fR and \fIout\fR are supported at
133 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
134 not the wiringPi number.
136 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
137 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
138 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
139 that of the user running the \fBgpio\fR program. This means that you
140 can have a small script of gpio exports to setup the gpio pins as your
141 program requires without the need to run anything as root, or with the
146 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
147 the direction to input and set the edge interrupt method to \fInone\fR,
148 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
149 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
152 Like the export commands above, ownership is set to that of the
153 calling user, allowing subsequent access from user programs without
158 Un-Export a GPIO pin in the /sys/class/gpio directory.
164 Change the pad driver value for the given pad group to the supplied drive
165 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
166 absolutely sure you know what you're doing.
170 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
174 Change the PWM range register. The default is 1024.
177 .B load i2c [baudrate]
178 This loads the i2c or drivers into the kernel and changes the permissions
179 on the associated /dev/ entries so that the current user has access to
180 them. Optionally it will set the I2C baudrate to that supplied (or as
181 close as the Pi can manage) The default speed is 100Kb/sec.
184 .B load spi [buffer size in KB]
185 This loads the the spi drivers into the kernel and changes the permissions
186 on the associated /dev/ entries so that the current user has access to
187 them. Optionally it will set the SPI buffer size to that supplied. The
194 This reads the analog to digital converter on the Gertboard on the given
195 channel. The board jumpers need to be in-place to do this operation.
201 This writes the supplied value to the output channel on the Gertboards
202 SPI digital to analogue converter.
203 The board jumpers need to be in-place to do this operation.
206 .SH "WiringPi vs. BCM_GPIO Pin numbering"
211 WiringPi GPIO-r1 GPIO-r2 Function
236 Note that "r1" and "r2" above refers to the board revision. Normally
237 wiringPi detects the correct board revision with use for it's own
238 numbering scheme, but if you are using a Revision 2 board with some
239 of the pins which change numbers between revisions you will need
240 to alter your software.
250 gpio mode 4 output # Set pin 4 to output
252 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
254 gpio mode 1 pwm # Set pin 1 to PWM mode
256 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
258 gpio export 17 out # Set GPIO Pin 17 to output
260 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
262 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
266 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
267 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
275 https://projects.drogon.net/raspberry-pi/wiringpi/
283 Please report bugs to <projects@drogon.net>
287 Copyright (c) 2012 Gordon Henderson
288 This is free software; see the source for copying conditions. There is NO
289 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
291 .SH TRADEMARKS AND ACKNOWLEDGEMENTS
293 Raspberry Pi is a trademark of the Raspberry Pi Foundation. See
294 http://raspberrypi.org/ for full details.