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RPi_Low-level_peripherals
BCM2835 GPIO functions
This is a wiki-fied copy of Table 6-31 from the BCM2835
datasheet
including any relevant
errata
, with a couple of extra columns, all nicely hyperlinked together and cross-referenced so that clicking on a function name will automatically take you to the description of that function.
Any GPIOs that aren't
connected
on the RaspberryPi Model B revision 1.0 circuit board are
crossed out
, and the GPIOs available on the
GPIO Connector (P1)
are in
bold
, with their default function (according to the
schematics
) in
bold italics
.
(If you want to see how GPIO-pins map back to
actual
pins, see
this page
). A selection of common circuits for interfacing with the GPIOs is given at
RPi_GPIO_Interface_Circuits
.
GPIO Pins Alternative Function Assignment
This next paragraph (which I've crossed out) only applies to Rev.1 boards, and even then these GPIOs were apparently never
actually
used for board identification!
Board revision coding
GPIO 28-31 are brought out, with each pin attached to a voltage divider. These four GPIO's are used to auto detect the revision version, as is indicated in the schematic (sheet to, location 7D). With 10K resistors either mounted or unmounted the pins are either pulled low or high, giving a four bit condition that can be read, with currently only two of the sixteen possible combinations used, one (code '0') for the model A and the other (code '1') for the model B, with codes '2' to 'F' reserved for future use.
As in the table above, the GPIOs available on the
GPIO Connector (P1)
are in
bold
, with their default function (according to the
schematics
) in
bold italics
.
Special function legend: