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/pwm/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 Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
61 system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
62 interface without needing to be run as root.
68 Output the current version including the board revision of the Raspberry Pi.
72 Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
76 Use the PiFace interface board and its corresponding pin numbers.
80 Read the digital value of the given pin and print 0 or 1 to represent the
81 respective logic levels.
84 .B write <pin> <value>
85 Write the given value (0 or 1) to the pin.
89 Output a table of all GPIO pins values. The values represent the actual values read
90 if the pin is in input mode, or the last value written if the pin is in output
95 Write a PWM value (0-1023) to the given pin.
99 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
100 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
101 pull-up, pull-down or tristate (off) controls.
105 Un-Export all the GPIO pins in the /sys/class/gpio directory.
109 Print a list (if any) of all the exported GPIO pins and their current values.
113 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
114 mode command above however only \fIin\fR and \fIout\fR are supported at
115 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
116 not the wiringPi number.
118 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
119 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
120 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
121 that of the user running the \fBgpio\fR program. This means that you
122 can have a small script of gpio exports to setup the gpio pins as your
123 program requires without the need to run anything as root, or with the
128 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
129 the direction to input and set the edge interrupt method to \fInone\fR,
130 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
131 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
134 Like the export commands above, ownership is set to that of the
135 calling user, allowing subsequent access from user programs without
140 Un-Export a GPIO pin in the /sys/class/gpio directory.
146 Change the pad driver value for the given pad group to the supplied drive
147 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
148 absolutely sure you know what you're doing.
152 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
156 Change the PWM range register. The default is 1024.
160 This loads the i2c or the spi drivers into the system and changes the permissions on
161 the associated /dev/ entries so that the current user has access to them.
167 This reads the analog to digital converter on the Gertboard on the given
168 channel. The board jumpers need to be in-place to do this operation.
174 This writes the supplied value to the output channel on the Gertboards
175 SPI digital to analogue converter.
176 The board jumpers need to be in-place to do this operation.
179 .SH "WiringPi vs. GPIO Pin numbering"
184 WiringPi GPIO-r1 GPIO-r2 Function
217 gpio mode 4 output # Set pin 4 to output
219 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
221 gpio mode 1 pwm # Set pin 1 to PWM mode
223 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
225 gpio export 17 out # Set GPIO Pin 17 to output
227 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
229 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
233 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
234 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
242 https://projects.drogon.net/raspberry-pi/wiringpi/
250 Please report bugs to <projects@drogon.net>
254 Copyright (c) 2012 Gordon Henderson
255 This is free software; see the source for copying conditions. There is NO
256 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
258 .SH TRADEMARKS AND ACKNOWLEDGEMENTS
260 Raspberry Pi is a trademark of the Raspberry Pi Foundation.