1 .TH "GPIO" "14 June 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/pwm/mode ...
20 .B unexportall/exports
23 .B export/edge/unexport
51 is a swiss army knife of a command line tool to allow the user easy
52 access to the GPIO pins on the Raspberry Pi and the SPI A/D and D/A
53 converters on the Gertboard. It's designed for simple testing and
54 diagnostic purposes, but can be used in shell scripts for general if
55 somewhat slow control of the GPIO pins.
57 Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
58 system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
59 interface without needing to be run as root.
65 Output the current version
69 Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
73 Use the PiFace interface board and its corresponding pin numbers.
77 Read the digital value of the given pin and print 0 or 1 to represent the
78 respective logic levels.
82 Write the given value (0 or 1) to the pin.
86 Write a PWM value (0-1023) to the given pin.
90 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
91 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
92 pull-up, pull-down or tristate (off) controls.
96 Un-Export all the GPIO pins in the /sys/class/gpio directory.
100 Print a list (if any) of all the exported GPIO pins and their current values.
104 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
105 mode command above however only \fIin\fR and \fIout\fR are supported at
106 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
107 not the wiringPi number.
109 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
110 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
111 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
112 that of the user running the \fBgpio\fR program. This means that you
113 can have a small script of gpio exports to setup the gpio pins as your
114 program requires without the need to run anything as root, or with the
119 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
120 the direction to input and set the edge interrupt method to \fInone\fR,
121 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
122 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
125 Like the export commands above, ownership is set to that of the
126 calling user, allowing subsequent access from user programs without
131 Un-Export a GPIO pin in the /sys/class/gpio directory.
137 Change the pad driver value for the given pad group to the supplied drive
138 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
139 absolutely sure you know what you're doing.
143 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
147 Change the PWM range register. The default is 1024.
151 This loads the i2c or the spi drivers into the system and changes the permissions on
152 the associated /dev/ entries so that the current user has access to them.
158 This reads the analog to digital converter on the Gertboard on the given
159 channel. The board jumpers need to be in-place to do this operation.
165 This writes the supplied value to the output channel on the Gertboards
166 SPI digital to analogue converter.
167 The board jumpers need to be in-place to do this operation.
170 .SH "WiringPi vs. GPIO Pin numbering"
175 WiringPi GPIO-r1 GPIO-r2 Function
208 gpio mode 4 output # Set pin 4 to output
210 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
212 gpio mode 1 pwm # Set pin 1 to PWM mode
214 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
216 gpio export 17 out # Set GPIO Pin 17 to output
218 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
220 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
224 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
225 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
233 https://projects.drogon.net/raspberry-pi/wiringpi/
241 Report bugs to <projects@drogon.net>
245 Copyright (c) 2012 Gordon Henderson
246 This is free software; see the source for copying conditions. There is NO
247 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.