OLIMEX A10-OLX-LIME [31/45] Gpio ports

6.9 GPIO ports

There are four GPIO ports which are used generally to access unused by the board's peripherals

pins. However, there are exceptions – some of the pins might be used to easily peripherals or their

levels.

Three of the GPIO connectors have 40 pins and the last one has 20 pins. Note that all GPIO

connectors have 0.05'' (50 mil) step between pins. Olimex sells a compatible extension cable for

these connectors named CABLE-40-40-10CM.

IMPORTANT: the cables and the 0.05'' connectors are very fragile – if you attempt to disconnect

the setup by pulling the cable it might break! Furthermore – you might bend the board's or the

cable's pins! Use pliers or other suitable object to disconnect the connectors carefully!

Most of the pins are already defined in default operating system images. Some of them can be used

as GPIOs, I2C or SPI without much of a problem. Information on the software usage of GPIO ports

might be found in chapters “2.7 GPIO under Debian” and “2.8 I2C and SPI under Debian”

6.9.1 GPIO-1 (General Purpose Input/Output) 40pin connector

The GPIO-1 connector has 40 pins. Note that the connector has 0.05'' (50 mil) step between pins.

Olimex also sells a compatible extension cable for the connector named CABLE-40-40-10CM.

IMPORTANT: the cables and the 0.05'' connectors are very fragile – if you attempt to disconnect

the setup by pulling the cable it might break! Furthermore – you might bend the board's or the

cable's pins! Use pliers or other suitable object to disconnect the connectors carefully!

This connector features the processor signals needed for audio headphones output and microphone

input. Please note that not only the connectors but also the rest of the schematic is missing! You

would need to add resistors and capacitors. The connector also has the signals needed for a VGA

output. The official Linux Debian images include a script that can be used to change the video

output to VGA. We don't provide Android images for the VGA video output.

Microphone signals are located on GPIO-1 connector: MICIN1 and VMIC

Headphone signals are located on GPIO-1 connector: HPOUTL, HPCOM and HPOUTR

Please note that part of the VGA and composite video signals are multiplexed (VGA-R, VGA-

B, VGA-G share the same pins with the TVOUT signals).

Composite video signals are located on GPIO-1 connector: TVOUT0 (GPIO-1 pin 20), TVOUT1

(GPIO-1 pin 22), TVOUT2 (GPIO-1 pin 24); you would also need AGND (GPIO-1 pin 4)

VGA signals are located at GPIO-1 connector and LCD_CON connector: The total of 5 signals you

need for VGA output can be split into two categories:

1) Data signals:

VGA-R (AC17); VGA-B (AB16); VGA-G (AC16)

2) Synchronization signals:

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