Pi GPIO Output Enable Register
|Short Description||Enables GPIO pins output|
Bits 27-0: Set bits enable GPIO output on the corresponding GPIO pin (soft reset = all 0)
GPIO pins 1:0 cannot be enabled.
The register $93 is MSB (most significant byte = bits 31-24), register $90 is LSB (least significant byte = bits 7-0).
Bits 31-28 are not explicitly specified in the docs, so consider them "Reserved, preserve current value".
(note: Next registers with number higher than $7F are inaccessible from Copper code)