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351 lines
9.2 KiB
351 lines
9.2 KiB
.TH GPIO 1 "March 2018" wiringPi "Command-Line access to Raspberry Pi's GPIO" |
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.SH NAME |
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gpio \- Command-line access to Raspberry Pi's 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 | \-1 ] |
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.B mode/read/write/aread/awrite/wb/pwm/pwnTone/clock/toggle/blink ... |
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.PP |
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.B gpio |
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.B [ \-x extension:params ] |
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.B mode/read/write/aread/awrite/pwm/toggle/blink ... |
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.PP |
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.B gpio |
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.B [ \-p ] |
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.B read/write/toggle/blink |
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.B ... |
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.PP |
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.B gpio |
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.B [ \-p ] |
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.B pwnTone pin frequency |
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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 wfi |
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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 usbp |
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high | low |
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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 \-1 |
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Use the physical pin numbers rather than wiringPi pin numbers. |
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\fINote:\fR that this applies to the P1 connector only. It is not possible to |
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use pins on the Revision 2 P5 connector this way, and as with \-g the |
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BCM_GPIO pin numbers are always used with the export and edge commands. |
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.TP |
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.B \-x extension |
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This causes the named extension to be initialised. Extensions |
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comprise of a name (e.g. mcp23017) followed by a colon, then the |
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pin-base, then more optional parameters depending on the extension type. |
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See the web page on http://wiringpi.com/the-gpio-utility/ |
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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. The PiFace |
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will always appear at pin number 200 in the gpio command. You can assign any |
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pin numbers you like in your own programs though. |
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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 toggle <pin> |
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Changes the state of a GPIO pin; 0 to 1, or 1 to 0. |
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Note unlike the blink command, the pin must be in output mode first. |
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.TP |
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.B blink <pin> |
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Blinks the given pin on/off. Press Control-C to exit. |
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Note: This command explicitly sets the pin to output mode. |
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.TP |
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.B aread <pin> |
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Read the analog value of the given pin. This needs to be used in |
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conjunction with a -x flag to add in an extension that handles analog |
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inputs. |
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e.g. gpio -x mcp3002:200:0 aread 200 |
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will read the first analog input on an mcp3002 SPI ADC chip. |
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.TP |
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.B awrite <pin> <value> |
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Write the analog value to the given pin. This needs to be used in |
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conjunction with a -x flag to add in an extension that handles analog |
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inputs. |
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e.g. gpio -x mcp4802:200:0 awrite 200 128 |
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will write the value 128 to the first DAC port on an mcp4802 chip on |
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the Pi's SPI bus 0. |
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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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The readall command is usable with an extension module (via the -x parameter), |
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but it's unable to determine pin modes or states, so will perform both a |
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digital and analog read on each pin in-turn. |
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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. The pin needs to be put |
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into PWM mode first. |
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.TP |
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.B clock <pin> <frequency> |
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Set the output frequency on the given pin. The pin needs to be put into |
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clock mode first. |
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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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The ALT modes can also be set using \fIalt0\fR, \fIalt1\fR, ... \fIalt5\fR. |
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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, \fIout\fR, \fIhigh\fR and |
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\fRlow\fR are supported at this time. Note that the pin number is the |
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\fBBCM_GPIO\fR number and not the wiringPi number. The \fIhigh\fR and |
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\fIlow\fR commands pre-set the output value at the same time as the |
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export to output mode. |
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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 wfi <pin> <mode> |
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This set the given pin to the supplied interrupt mode: rising, falling |
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or both then waits for the interrupt to happen. It's a non-busy wait, |
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so does not consume and CPU while it's waiting. |
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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 usbp |
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high | low |
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Change the USB current limiter to high (1.2 amps) or low (the default, 600mA) |
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This is only applicable to the Model B+ and the Model B, v2. |
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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 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 vs. Physical pin numbering" |
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.PP |
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The quickest way to get a list of the pin differences is to run the command |
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.TP |
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gpio readall |
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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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As of kernels 4.1.7, a user-level GPIO access mechanism is available, |
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however wiringPi will not use this by default - because at this time |
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there appears to be issues when trying to program the PWM or clock output |
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hardware. If you can live without PWM or GPIO clocks and you want to use |
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the GPIO from a non-root program, then you need to make sure that the |
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module \fIbcm2835_gpiomem\fR is loaded at boot time. This should happen |
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automatically when you enable the device tree in raspi-config. You may |
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also need some additional information in /etc/udev/rules.d/ to change the |
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mode and ownership of the /dev/gpiomem file. Finally, you need to set |
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the environment variable \fIWIRINGPI_GPIOMEM\fR. This will go-away |
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in future releases once the /dev/gpiomem interface is fully operational. |
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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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http://wiringpi.com/ |
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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) 2012-2018 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. See |
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http://raspberrypi.org/ for full details.
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