-.TH "GPIO" "March 2013" "Command-Line access to Raspberry Pi's GPIO"
+.TH "GPIO" "January 2015" "Command-Line access to Raspberry Pi's GPIO"
.SH NAME
gpio \- Command-line access to Raspberry Pi's GPIO
.B ...
.PP
.B gpio
-.B readall/reset
+.B readall
.PP
.B gpio
.B unexportall/exports
but it's unable to determine pin modes or states, so will perform both a
digital and analog read on each pin in-turn.
-.TP
-.B reset
-Resets the GPIO - As much as it's possible to do. All pins are set to
-input mode and all the internal pull-up/down resistors are disconnected
-(tristate mode).
-
-The reset command is usable with an extension module (via the -x parameter),
-but it's limited to turning the pin into input mode (if applicable) and
-removing any pull up/down resistor.
-
.TP
.B pwm <pin> <value>
Write a PWM value (0-1023) to the given pin. The pin needs to be put
use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
pull-up, pull-down or tristate (off) controls.
+The ALT modes can also be set using \fIalt0\fR, \fIalt1\fR, ... \fIalt5\fR.
+
.TP
.B unexportall
Un-Export all the GPIO pins in the /sys/class/gpio directory.
them. Optionally it will set the I2C baudrate to that supplied in Kb/sec
(or as close as the Pi can manage) The default speed is 100Kb/sec.
+Note that on a Pi with a recent 3.18 kernel with the device-tree structure
+enable, the load may fail until you add:
+
+.I dtparam=i2c=on
+
+into \fB/boot/config.txt\fR to allow user use of the I2C bus.
+
.TP
-.B load spi [buffer size in KB]
+.B load spi
This loads the spi drivers into the kernel and changes the permissions
on the associated /dev/ entries so that the current user has access to
-them. Optionally it will set the SPI buffer size to that supplied. The
-default is 4KB.
+them. It used to have the ability to change the buffer size from the
+default of 4096 bytes to an arbitary value, however for some time the
+Pi Foundation have compiled the SPI device driver into the kernel and
+this has fixed the buffer size. The way to change it now is to edit
+the /boot/cmdline.txt file and add on spdev.bufsiz=8192 to set it to
+e.g. 8192 bytes then reboot.
+
+Note that on a Pi with a recent 3.18 kernel with the device-tree structure
+enable, the load may fail until you add:
+
+.I dtparam=spi=on
+
+into \fB/boot/config.txt\fR to allow user use of the I2C bus.
.TP
.B gbr
The board jumpers need to be in-place to do this operation.
-.SH "WiringPi vs. BCM_GPIO Pin numbering"
+.SH "WiringPi vs. BCM_GPIO Pin numbering vs. Physical pin numbering"
.PP
-.TS
-c c c c l.
-WiringPi GPIO-r1 GPIO-r2 P1-Phys Function
-_
- 0 17 17 11
- 1 18 18 12 (PWM)
- 2 21 27 13
- 3 22 22 15
- 4 23 23 16
- 5 24 24 18
- 6 25 25 22
- 7 4 4 7
- 8 0 2 3 I2C: SDA0
- 9 1 3 5 I2C: SCL0
-10 8 8 24 SPI: CE0
-11 7 7 26 SPI: CE1
-12 10 10 19 SPI: MOSI
-13 9 9 21 SPI: MISO
-14 11 11 23 SPI: SCLK
-15 14 14 8 TxD
-16 15 16 10 RxD
-17 - 28
-18 - 29
-19 - 30
-20 - 31
-.TE
-
-Note that "r1" and "r2" above refers to the board revision. Normally
-wiringPi detects the correct board revision with use for it's own
-numbering scheme, but if you are using a Revision 2 board with some
-of the pins which change numbers between revisions you will need
-to alter your software.
+The quickest way to get a list of the pin differences is to run the command
+.TP
+gpio readall
.SH FILES
.SH COPYRIGHT
-Copyright (c) 2012-2013 Gordon Henderson
+Copyright (c) 2012-2015 Gordon Henderson
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
~ianmdlvl / wiringPi.git / blobdiff