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/pwmTone ...
20 .B read/write/toggle/wb
27 .B unexportall/exports
30 .B export/edge/unexport
66 is a swiss army knife of a command line tool to allow the user easy
67 access to the GPIO pins on the Raspberry Pi and the SPI A/D and D/A
68 converters on the Gertboard. It's designed for simple testing and
69 diagnostic purposes, but can be used in shell scripts for general if
70 somewhat slow control of the GPIO pins.
72 It can also control the IO's on the PiFace IO board and load the SPI and I2C
73 kernel modules if required.
75 Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
76 system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
77 interface without needing to be run as root.
83 Output the current version including the board revision of the Raspberry Pi.
87 Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
88 \fINote:\fR The BCM_GPIO pin numbers are always used with the
89 export and edge commands.
93 Use the physical pin numbers rather than wiringPi pin numbers.
94 \fINote:\fR that this applies to the P1 connector only. It is not possible to
95 use pins on the Revision 2 P5 connector this way, and as with \-g the
96 BCM_GPIO pin numbers are always used with the export and edge commands.
100 This causes the named extension to be initialised. Extensions
101 comprise of a name (e.g. mcp23017) followed by a colon, then the
102 pin-base, then more optional parameters depending on the extension type.
103 See the web page on http://wiringpi.com/the-gpio-utility/
107 Use the PiFace interface board and its corresponding pin numbers. The PiFace
108 will always appear at pin number 200 in the gpio command. You can assign any
109 pin numbers you like in your own programs though.
113 Read the digital value of the given pin and print 0 or 1 to represent the
114 respective logic levels.
117 .B write <pin> <value>
118 Write the given value (0 or 1) to the pin. You need to set the pin
119 to output mode first.
123 Read the analog value of the given pin. This needs to be uses in
124 conjunction with a -x flag to add in an extension that handles analog
125 inputs. respective logic levels.
127 e.g. gpio -x mcp3002:200:0 aread 200
129 will read the first analog input on an mcp3002 SPI ADC chip.
132 .B awrite <pin> <value>
133 Write the analog value to the given pin. This needs to be used in
134 conjunction with a -x flag to add in an extension that handles analog
135 inputs. respective logic levels.
137 e.g. gpio -x mcp4802:200:0 awrite 200 128
139 will write the value 128 to the first DAC port on an mcp4802 chip on
145 Write the given byte to the 8 main GPIO pins. You can prefix it with 0x
146 to specify a hexadecimal number. You need to set pins to output mode
151 Output a table of all GPIO pins values. The values represent the actual values read
152 if the pin is in input mode, or the last value written if the pin is in output
155 The readall command is usable with an extension module (via the -x parameter),
156 but it's unable to determine pin modes or states, so will perform both a
157 digital and analog read on each pin in-turn.
161 Resets the GPIO - As much as it's possible to do. All pins are set to
162 input mode and all the internal pull-up/down resistors are disconnected
165 The reset command is usable with an extension module (via the -x parameter),
166 but it's limited to turning the pin into input mode (if applicable) and
167 removing any pull up/down resistor.
171 Write a PWM value (0-1023) to the given pin. The pin needs to be put
175 .B clock <pin> <frequency>
176 Set the output frequency on the given pin. The pin needs to be put into
181 Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
182 use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
183 pull-up, pull-down or tristate (off) controls.
187 Un-Export all the GPIO pins in the /sys/class/gpio directory.
191 Print a list (if any) of all the exported GPIO pins and their current values.
195 Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
196 mode command above however only \fIin\fR and \fIout\fR are supported at
197 this time. Note that the pin number is the \fBBCM_GPIO\fR number and
198 not the wiringPi number.
200 Once a GPIO pin has been exported, the \fBgpio\fR program changes the
201 ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
202 later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
203 that of the user running the \fBgpio\fR program. This means that you
204 can have a small script of gpio exports to setup the gpio pins as your
205 program requires without the need to run anything as root, or with the
210 This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
211 the direction to input and set the edge interrupt method to \fInone\fR,
212 \fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
213 above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
216 Like the export commands above, ownership is set to that of the
217 calling user, allowing subsequent access from user programs without
222 Un-Export a GPIO pin in the /sys/class/gpio directory.
226 This set the given pin to the supplied interrupt mode: rising, falling
227 or both then waits for the interrupt to happen. It's a non-busy wait,
228 so does not consume and CPU while it's waiting.
234 Change the pad driver value for the given pad group to the supplied drive
235 value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
236 absolutely sure you know what you're doing.
242 Change the USB current limiter to high (1.2 amps) or low (the default, 600mA)
243 This is only applicable to the model B+
247 Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
251 Change the PWM range register. The default is 1024.
254 .B load i2c [baudrate]
255 This loads the i2c or drivers into the kernel and changes the permissions
256 on the associated /dev/ entries so that the current user has access to
257 them. Optionally it will set the I2C baudrate to that supplied in Kb/sec
258 (or as close as the Pi can manage) The default speed is 100Kb/sec.
261 .B load spi [buffer size in KB]
262 This loads the spi drivers into the kernel and changes the permissions
263 on the associated /dev/ entries so that the current user has access to
264 them. Optionally it will set the SPI buffer size to that supplied. The
271 This reads the analog to digital converter on the Gertboard on the given
272 channel. The board jumpers need to be in-place to do this operation.
278 This writes the supplied value to the output channel on the Gertboards
279 SPI digital to analogue converter.
280 The board jumpers need to be in-place to do this operation.
283 .SH "WiringPi vs. BCM_GPIO Pin numbering"
288 WiringPi GPIO-r1 GPIO-r2 P1-Phys Function
302 12 10 10 19 SPI: MOSI
304 14 11 11 23 SPI: SCLK
313 Note that "r1" and "r2" above refers to the board revision. Normally
314 wiringPi detects the correct board revision with use for it's own
315 numbering scheme, but if you are using a Revision 2 board with some
316 of the pins which change numbers between revisions you will need
317 to alter your software.
327 gpio mode 4 output # Set pin 4 to output
329 gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
331 gpio mode 1 pwm # Set pin 1 to PWM mode
333 gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
335 gpio export 17 out # Set GPIO Pin 17 to output
337 gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
339 gpio -g read 0 # Read GPIO Pin 0 (SDA0)
343 When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
344 pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
360 Please report bugs to <projects@drogon.net>
364 Copyright (c) 2012-2013 Gordon Henderson
365 This is free software; see the source for copying conditions. There is NO
366 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
368 .SH TRADEMARKS AND ACKNOWLEDGEMENTS
370 Raspberry Pi is a trademark of the Raspberry Pi Foundation. See
371 http://raspberrypi.org/ for full details.