ATAPIHat

Overview

Replaced by https://github.com/Manawyrm/ATAPIHat-SMI
Directly connected to the GPIOs, much higher speeds.

Don't manufacture this board (in either Rev.A or Rev.B).
This design isn't optimal at all.

Rev. A Errata

Reset is wrong, is hardpulled to ground. Solution: connect to GPIO17.
Chip select is non-ideal (solder jumper?)
Selectable 5V/3.3V on Pin 20 required
IDE Reset line should be connected to LED7 aka pin 28 of U4
Signal integrity issues, paralell termination resistors (maybe 120 Ohms) and series termination would be ideal.

Additional info

Kernel driver
Schematic