84PCE:Ports:0009

Synopsis

Port Number: 0009

Function: GPIO A Output

Details

These GPIOs appear to be connected to power control.

Bits [1:0]

Latches value written, no apparent effect.

Bit [2]

Likely connected to the LCD's reset line, which is active low. After being set, the LCD must be given a sequence of initialization commands before it can display an image again.

Bit [3]

Latches value written, no apparent effect. Connected to test point TP06A on rev. C - might be different on newer hardware revisions?

Bit [4]

SPI slave select - reset to communicate with the LCD, set to communicate with the Python coprocessor. Connected to test point TP09A on rev. C - might be different on newer hardware revisions?

Bits [7:5]

Latches value written, no apparent effect.