This is IDE (ATA) hard disk adapter for Atari Mega ST machines.
Goes into it's expansion bus, but you must solder couple points as +5V and INTR line.
Documentation is for Eagle 4.16, light version, what is free.

Circuit is design of Pera Putnik (ppera) and is simplified version of circuit/schematic from 1992 - instead GAL20 we have here GAL16, no data line driver chips. TOS 2.06 support is for 2 chips instead 4.

Schematic drawing and board design is done by Jozsef Vas (jvas) ..

http://www.ppest.org

