IDE interface for ST question : memory map, emutos
Posted: 28 Aug 2025 23:19
Hello, theses days I am looking at the IDE interfaces for the ST, that are using the CPU bus and a GAL for some signalling, and I would like to know whether I understand correctly, so here are my findings and understanding, could you please confirm or correct me ?
I can only find one instance of resources, at PP's page :
If I correctly understand the GAL listing :
In other words, it uses address range $F00000--$F03FFF, use address bit 5 to assert either IDE CS0 or CS1 and bits 2 to 4 of the address bus are mapped to IDE A0 to A2 respectively, to select the Command/Control register
Emutos Support ?
None, from what I can read in the IDE driver : https://github.com/emutos/emutos/blob/master/bios/ide.c
Emutos supports only the Falcon IDE controller and (that is mapped to address range 0xF00000--0xFA0000 by the way) the FireBee CF card.
I can only find one instance of resources, at PP's page :
- schematic : https://atari.8bitchip.info/aidesch.htm
- GAL source : https://atari.8bitchip.info/t206ide.gal
If I correctly understand the GAL listing :
Code: Select all
// Addresse bus
/SELP = 1111.0000.00--.----.--0-.---- // IDE CS0 select the Command Block Registers
/SELS = 1111.0000.00--.----.--1-.---- // IDE CS1 select the Control Block Registers ; CS0 XOR CS1 always true at assertion time
/IORD = 1111.0000.00--.----.----.---- // READ strobe
/IORW = 1111.0000.00--.----.----.---- // WRITE strobe
A0 = ----.----.----.----.----.-x--
A1 = ----.----.----.----.----.x---
A2 = ----.----.----.----.---x.----
Emutos Support ?
None, from what I can read in the IDE driver : https://github.com/emutos/emutos/blob/master/bios/ide.c
Emutos supports only the Falcon IDE controller and (that is mapped to address range 0xF00000--0xFA0000 by the way) the FireBee CF card.