1 .TH "GPIO" "March 2013" "Command-Line access to Raspberry Pi's GPIO"
4 gpio \- Command-line access to Raspberry Pi's GPIO
12 .B mode/read/write/aread/awrite/wb/pwm/clock ...
15 .B [ \-x extension:params ]
16 .B mode/read/write/aread/awrite/pwm ...
27 .B unexportall/exports
30 .B export/edge/unexport
62 is a swiss army knife of a command line tool to allow the user easy
63 access to the GPIO pins on the Raspberry Pi and the SPI A/D and D/A
64 converters on the Gertboard. It's designed for simple testing and
65 diagnostic purposes, but can be used in shell scripts for general if
66 somewhat slow control of the GPIO pins.
68 It can also control the IO's on the PiFace IO board and load the SPI and I2C
69 kernel modules if required.
71 Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
72 system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
73 interface without needing to be run as root.
79 Output the current version including the board revision of the Raspberry Pi.
83 Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
84 \fINote:\fR The BCM_GPIO pin numbers are always used with the
85 export and edge commands.
89 Use the physical pin numbers rather than wiringPi pin numbers.
90 \fINote:\fR that this applies to the P1 connector only. It is not possible to
91 use pins on the Revision 2 P5 connector this way, and as with \-g the
92 BCM_GPIO pin numbers are always used with the export and edge commands.
96 This causes the named extension to be initialised. Extensions
97 comprise of a name (e.g. mcp23017) followed by a colon, then the
98 pin-base, then more optional parameters depending on the extension type.
99 See the web page on http://wiringpi.com/the-gpio-utility/
103 Use the PiFace interface board and its corresponding pin numbers. The PiFace
104 will always appear at pin number 200 in the gpio command. You can assign any
105 pin numbers you like in your own programs though.
109 Read the digital value of the given pin and print 0 or 1 to represent the
110 respective logic levels.
113 .B write <pin> <value>
114 Write the given value (0 or 1) to the pin. You need to set the pin
115 to output mode first.
119 Write the given byte to the 8 main GPIO pins. You can prefix it with 0x
120 to specify a hexadecimal number. You need to set pins to output mode
125 Output a table of all GPIO pins values. The values represent the actual values read
126 if the pin is in input mode, or the last value written if the pin is in output
129 The readall command is usable with an extension module (via the -x parameter),
130 but it's unable to determine pin modes or states, so will perform both a
131 digital and analog read on each pin in-turn.
135 Resets the GPIO - As much as it's possible to do. All pins are set to input
136 mode and all the internal pull-up/down resistors are disconnected (tristate mode).
138 The reset command is usable with an extension module (via the -x parameter),
139 but it's limited to turning the pin into input mode (if applicable) and
140 removing any pull up/down resistor.
144 Write a PWM value (0-1023) to the given pin. The pin needs to be put
148 .B clock <pin> <frequency>
149 Set the output frequency on the given pin. The pin needs to be put into
154 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
155 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
156 pull-up, pull-down or tristate (off) controls.
160 Un-Export all the GPIO pins in the /sys/class/gpio directory.
164 Print a list (if any) of all the exported GPIO pins and their current values.
168 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
169 mode command above however only \fIin\fR and \fIout\fR are supported at
170 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
171 not the wiringPi number.
173 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
174 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
175 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
176 that of the user running the \fBgpio\fR program. This means that you
177 can have a small script of gpio exports to setup the gpio pins as your
178 program requires without the need to run anything as root, or with the
183 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
184 the direction to input and set the edge interrupt method to \fInone\fR,
185 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
186 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
189 Like the export commands above, ownership is set to that of the
190 calling user, allowing subsequent access from user programs without
195 Un-Export a GPIO pin in the /sys/class/gpio directory.
199 This set the given pin to the supplied interrupt mode: rising, falling
200 or both then waits for the interrupt to happen. It's a non-busy wait,
201 so does not consume and CPU while it's waiting.
207 Change the pad driver value for the given pad group to the supplied drive
208 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
209 absolutely sure you know what you're doing.
213 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
217 Change the PWM range register. The default is 1024.
220 .B load i2c [baudrate]
221 This loads the i2c or drivers into the kernel and changes the permissions
222 on the associated /dev/ entries so that the current user has access to
223 them. Optionally it will set the I2C baudrate to that supplied in Kb/sec
224 (or as close as the Pi can manage) The default speed is 100Kb/sec.
227 .B load spi [buffer size in KB]
228 This loads the spi drivers into the kernel and changes the permissions
229 on the associated /dev/ entries so that the current user has access to
230 them. Optionally it will set the SPI buffer size to that supplied. The
237 This reads the analog to digital converter on the Gertboard on the given
238 channel. The board jumpers need to be in-place to do this operation.
244 This writes the supplied value to the output channel on the Gertboards
245 SPI digital to analogue converter.
246 The board jumpers need to be in-place to do this operation.
249 .SH "WiringPi vs. BCM_GPIO Pin numbering"
254 WiringPi GPIO-r1 GPIO-r2 P1-Phys Function
268 12 10 10 19 SPI: MOSI
270 14 11 11 23 SPI: SCLK
279 Note that "r1" and "r2" above refers to the board revision. Normally
280 wiringPi detects the correct board revision with use for it's own
281 numbering scheme, but if you are using a Revision 2 board with some
282 of the pins which change numbers between revisions you will need
283 to alter your software.
293 gpio mode 4 output # Set pin 4 to output
295 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
297 gpio mode 1 pwm # Set pin 1 to PWM mode
299 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
301 gpio export 17 out # Set GPIO Pin 17 to output
303 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
305 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
309 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
310 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
326 Please report bugs to <projects@drogon.net>
330 Copyright (c) 2012-2013 Gordon Henderson
331 This is free software; see the source for copying conditions. There is NO
332 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
334 .SH TRADEMARKS AND ACKNOWLEDGEMENTS
336 Raspberry Pi is a trademark of the Raspberry Pi Foundation. See
337 http://raspberrypi.org/ for full details.