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/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. You need to set the pin
90 Write the given byte to the 8 main GPIO pins. You can prefix it with 0x
91 to specify a hexadecimal number. You need to set pins to output mode
96 Output a table of all GPIO pins values. The values represent the actual values read
97 if the pin is in input mode, or the last value written if the pin is in output
102 Write a PWM value (0-1023) to the given pin.
106 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
107 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
108 pull-up, pull-down or tristate (off) controls.
112 Un-Export all the GPIO pins in the /sys/class/gpio directory.
116 Print a list (if any) of all the exported GPIO pins and their current values.
120 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
121 mode command above however only \fIin\fR and \fIout\fR are supported at
122 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
123 not the wiringPi number.
125 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
126 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
127 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
128 that of the user running the \fBgpio\fR program. This means that you
129 can have a small script of gpio exports to setup the gpio pins as your
130 program requires without the need to run anything as root, or with the
135 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
136 the direction to input and set the edge interrupt method to \fInone\fR,
137 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
138 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
141 Like the export commands above, ownership is set to that of the
142 calling user, allowing subsequent access from user programs without
147 Un-Export a GPIO pin in the /sys/class/gpio directory.
153 Change the pad driver value for the given pad group to the supplied drive
154 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
155 absolutely sure you know what you're doing.
159 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
163 Change the PWM range register. The default is 1024.
167 This loads the i2c or the spi drivers into the system and changes the permissions on
168 the associated /dev/ entries so that the current user has access to them.
174 This reads the analog to digital converter on the Gertboard on the given
175 channel. The board jumpers need to be in-place to do this operation.
181 This writes the supplied value to the output channel on the Gertboards
182 SPI digital to analogue converter.
183 The board jumpers need to be in-place to do this operation.
186 .SH "WiringPi vs. GPIO Pin numbering"
191 WiringPi GPIO-r1 GPIO-r2 Function
224 gpio mode 4 output # Set pin 4 to output
226 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
228 gpio mode 1 pwm # Set pin 1 to PWM mode
230 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
232 gpio export 17 out # Set GPIO Pin 17 to output
234 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
236 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
240 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
241 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
249 https://projects.drogon.net/raspberry-pi/wiringpi/
257 Please report bugs to <projects@drogon.net>
261 Copyright (c) 2012 Gordon Henderson
262 This is free software; see the source for copying conditions. There is NO
263 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
265 .SH TRADEMARKS AND ACKNOWLEDGEMENTS
267 Raspberry Pi is a trademark of the Raspberry Pi Foundation.