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
131 Resets the GPIO - As much as it's possible to do. All pins are set to input
132 mode and all the internal pull-up/down resistors are disconnected (tristate mode).
136 Write a PWM value (0-1023) to the given pin. The pin needs to be put
140 .B clock <pin> <frequency>
141 Set the output frequency on the given pin. The pin needs to be put into
146 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
147 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
148 pull-up, pull-down or tristate (off) controls.
152 Un-Export all the GPIO pins in the /sys/class/gpio directory.
156 Print a list (if any) of all the exported GPIO pins and their current values.
160 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
161 mode command above however only \fIin\fR and \fIout\fR are supported at
162 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
163 not the wiringPi number.
165 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
166 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
167 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
168 that of the user running the \fBgpio\fR program. This means that you
169 can have a small script of gpio exports to setup the gpio pins as your
170 program requires without the need to run anything as root, or with the
175 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
176 the direction to input and set the edge interrupt method to \fInone\fR,
177 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
178 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
181 Like the export commands above, ownership is set to that of the
182 calling user, allowing subsequent access from user programs without
187 Un-Export a GPIO pin in the /sys/class/gpio directory.
191 This set the given pin to the supplied interrupt mode: rising, falling
192 or both then waits for the interrupt to happen. It's a non-busy wait,
193 so does not consume and CPU while it's waiting.
199 Change the pad driver value for the given pad group to the supplied drive
200 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
201 absolutely sure you know what you're doing.
205 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
209 Change the PWM range register. The default is 1024.
212 .B load i2c [baudrate]
213 This loads the i2c or drivers into the kernel and changes the permissions
214 on the associated /dev/ entries so that the current user has access to
215 them. Optionally it will set the I2C baudrate to that supplied (or as
216 close as the Pi can manage) The default speed is 100Kb/sec.
219 .B load spi [buffer size in KB]
220 This loads the spi drivers into the kernel and changes the permissions
221 on the associated /dev/ entries so that the current user has access to
222 them. Optionally it will set the SPI buffer size to that supplied. The
229 This reads the analog to digital converter on the Gertboard on the given
230 channel. The board jumpers need to be in-place to do this operation.
236 This writes the supplied value to the output channel on the Gertboards
237 SPI digital to analogue converter.
238 The board jumpers need to be in-place to do this operation.
241 .SH "WiringPi vs. BCM_GPIO Pin numbering"
246 WiringPi GPIO-r1 GPIO-r2 P1-Phys Function
260 12 10 10 19 SPI: MOSI
262 14 11 11 23 SPI: SCLK
271 Note that "r1" and "r2" above refers to the board revision. Normally
272 wiringPi detects the correct board revision with use for it's own
273 numbering scheme, but if you are using a Revision 2 board with some
274 of the pins which change numbers between revisions you will need
275 to alter your software.
285 gpio mode 4 output # Set pin 4 to output
287 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
289 gpio mode 1 pwm # Set pin 1 to PWM mode
291 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
293 gpio export 17 out # Set GPIO Pin 17 to output
295 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
297 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
301 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
302 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
318 Please report bugs to <projects@drogon.net>
322 Copyright (c) 2012-2013 Gordon Henderson
323 This is free software; see the source for copying conditions. There is NO
324 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
326 .SH TRADEMARKS AND ACKNOWLEDGEMENTS
328 Raspberry Pi is a trademark of the Raspberry Pi Foundation. See
329 http://raspberrypi.org/ for full details.