The exact same code (down to the PIN numbers) works flawlessly with an ATF22v10C, but with a 16v8 the machine (an H5) doesn't boot and stays on a very colourful screen.
The only difference I've found between the two GALs is that the 16v8 has a weak pull-up to VCC on all pins while the 22v10 hasn't.
If anyone has a clue on the issue, I have a stock of 16v8 and only a few 22v10.
I simply connect the GAL directly to the CPU socket and the ROM2 signal (JP13 on the H5).
Here is the pretty simple code:
Code: Select all
Name STROMDEC ;
PartNo 00 ;
Date 12/23/2020 ;
Revision 01 ;
Designer Olivier ;
Company home ;
Assembly None ;
Location home ;
Device g22v10 ;
/* *************** CONNECTIONS ******************* */
/* ATARI A23..A16 = GAL 1..8 */
/* ATARI AS = GAL 9 */
/* ATARI RW = GAL 13 */
/* ATARI ROM2 = GAL 14 */
/* ATARI DTACK = GAL 17 */
/* ROM CE = GAL 15 */
/* ************************************************ */
/* *************** INPUT PINS ******************** */
PIN [1..8] = [A16..23] ;
PIN 9 = !AS ;
PIN 13 = RW ;
PIN 14 = !ROM2 ;
/* *************** OUTPUT PINS ******************** */
PIN 17 = !DTACK ;
PIN 18 = !CE ;
FIELD TOS = [A23..16];
/* *************** DECLARATIONS AND INTERMEDIATE VARIABLE DEFINITIONS ******************** */
CE256 = RW & AS & TOS:'h'[E00000..E3FFFF] ;
/* *************** ROM DECODER ******************** */
DTACK = CE256 ;
DTACK.oe = CE256 ;
CE = CE256 # ROM2 ;