mirror of
https://github.com/clockworkpi/WiringPi.git
synced 2025-12-12 16:08:49 +01:00
13bbba7a22
and developed the new ISR - Interrupt Service Routine handler - much easier than the old waitForInterrupt code! Minor tweaks to the gpio program to recognise the environment variable WIRINGPI_DEBUG too, and removed the printing of the errors from the main wiringPi setup routines (and added some new ones!)
279 lines
6.3 KiB
Groff
279 lines
6.3 KiB
Groff
.TH "GPIO" "21st October 2012" "Command-Line access to Raspberry Pi and PiFace GPIO"
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.SH NAME
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gpio \- Command-line access to Raspberry Pi and PiFace GPIO
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.SH SYNOPSIS
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.B gpio
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.B \-v
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.PP
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.B gpio
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.B [ \-g ]
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.B read/write/wb/pwm/mode ...
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.PP
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.B gpio
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.B [ \-p ]
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.B read/write/wb
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.B ...
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.PP
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.B gpio
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.B readall
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.PP
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.B gpio
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.B unexportall/exports
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.PP
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.B gpio
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.B export/edge/unexport
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.B ...
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.PP
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.B gpio
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.B drive
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group value
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.PP
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.B gpio
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.B pwm-bal/pwm-ms
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.PP
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.B gpio
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.B pwmr
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range
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.PP
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.B gpio
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.B load \ i2c/spi
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.PP
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.B gpio
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.B gbr
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channel
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.PP
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.B gpio
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.B gbw
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channel value
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.SH DESCRIPTION
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.B GPIO
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is a swiss army knife of a command line tool to allow the user easy
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access to the GPIO pins on the Raspberry Pi and the SPI A/D and D/A
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converters on the Gertboard. It's designed for simple testing and
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diagnostic purposes, but can be used in shell scripts for general if
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somewhat slow control of the GPIO pins.
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It can also control the IO's on the PiFace IO board and load the SPI and I2C
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kernel modules if required.
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Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
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system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
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interface without needing to be run as root.
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.SH OPTIONS
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.TP
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.B \-v
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Output the current version including the board revision of the Raspberry Pi.
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.TP
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.B \-g
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Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
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\fINOTE:\fR The BCM_GPIO pin numbers are always used with the
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export and edge commands.
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.TP
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.B \-p
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Use the PiFace interface board and its corresponding pin numbers.
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.TP
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.B read <pin>
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Read the digital value of the given pin and print 0 or 1 to represent the
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respective logic levels.
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.TP
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.B write <pin> <value>
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Write the given value (0 or 1) to the pin. You need to set the pin
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to output mode first.
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.TP
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.B wb <value>
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Write the given byte to the 8 main GPIO pins. You can prefix it with 0x
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to specify a hexadecimal number. You need to set pins to output mode
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first.
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.TP
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.B readall
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Output a table of all GPIO pins values. The values represent the actual values read
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if the pin is in input mode, or the last value written if the pin is in output
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mode.
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.TP
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.B pwm <pin> <value>
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Write a PWM value (0-1023) to the given pin.
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.TP
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.B mode <pin> <mode>
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Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
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use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
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pull-up, pull-down or tristate (off) controls.
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.TP
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.B unexportall
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Un-Export all the GPIO pins in the /sys/class/gpio directory.
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.TP
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.B exports
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Print a list (if any) of all the exported GPIO pins and their current values.
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.TP
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.B export
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Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
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mode command above however only \fIin\fR and \fIout\fR are supported at
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this time. Note that the pin number is the \fBBCM_GPIO\fR number and
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not the wiringPi number.
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Once a GPIO pin has been exported, the \fBgpio\fR program changes the
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ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
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later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
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that of the user running the \fBgpio\fR program. This means that you
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can have a small script of gpio exports to setup the gpio pins as your
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program requires without the need to run anything as root, or with the
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sudo command.
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.TP
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.B edge
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This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
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the direction to input and set the edge interrupt method to \fInone\fR,
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\fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
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above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
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numbering.
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Like the export commands above, ownership is set to that of the
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calling user, allowing subsequent access from user programs without
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requiring root/sudo.
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.TP
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.B unexport
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Un-Export a GPIO pin in the /sys/class/gpio directory.
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.TP
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.B drive
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group value
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Change the pad driver value for the given pad group to the supplied drive
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value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
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absolutely sure you know what you're doing.
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.TP
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.B pwm-bal/pwm-ms
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Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
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.TP
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.B pwmr
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Change the PWM range register. The default is 1024.
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.TP
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.B load i2c/spi
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This loads the i2c or the spi drivers into the system and changes the permissions on
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the associated /dev/ entries so that the current user has access to them.
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.TP
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.B gbr
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channel
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This reads the analog to digital converter on the Gertboard on the given
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channel. The board jumpers need to be in-place to do this operation.
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.TP
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.B gbw
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channel value
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This writes the supplied value to the output channel on the Gertboards
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SPI digital to analogue converter.
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The board jumpers need to be in-place to do this operation.
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.SH "WiringPi vs. BCM_GPIO Pin numbering"
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.PP
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.TS
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r r r l.
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WiringPi GPIO-r1 GPIO-r2 Function
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_
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0 17 17
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1 18 18 (PWM)
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2 21 27
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3 22 22
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4 23 23
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5 24 24
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6 25 25
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7 4 4
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8 0 2 I2C: SDA0
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9 1 3 I2C: SCL0
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10 8 8 SPI: CE0
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11 7 7 SPI: CE1
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12 10 10 SPI: MOSI
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13 9 9 SPI: MISO
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14 11 11 SPI: SCLK
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15 14 14 TxD
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16 15 16 RxD
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17 - 28
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18 - 29
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19 - 30
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20 - 31
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.TE
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Note that "r1" and "r2" above refers to the board revision. Normally
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wiringPi detects the correct board revision with use for it's own
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numbering scheme, but if you are using a Revision 2 board with some
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of the pins which change numbers between revisions you will need
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to alter your software.
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.SH FILES
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.TP 2.2i
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.I gpio
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executable
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.SH EXAMPLES
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.TP 2.2i
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gpio mode 4 output # Set pin 4 to output
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.PP
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gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
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.PP
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gpio mode 1 pwm # Set pin 1 to PWM mode
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.PP
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gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
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.PP
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gpio export 17 out # Set GPIO Pin 17 to output
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.PP
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gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
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.PP
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gpio -g read 0 # Read GPIO Pin 0 (SDA0)
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.SH "NOTES"
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When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
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pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
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pin numbers.
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.SH "SEE ALSO"
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.LP
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WiringPi's home page
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.IP
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https://projects.drogon.net/raspberry-pi/wiringpi/
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.SH AUTHOR
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Gordon Henderson
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.SH "REPORTING BUGS"
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Please report bugs to <projects@drogon.net>
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.SH COPYRIGHT
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Copyright (c) 2012 Gordon Henderson
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This is free software; see the source for copying conditions. There is NO
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warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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.SH TRADEMARKS AND ACKNOWLEDGEMENTS
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Raspberry Pi is a trademark of the Raspberry Pi Foundation.
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