Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Spedez on November 06, 2022, 08:18:22 AM
-
Any of you hackers have idea is it doable to have hardware on/off switch to enable/disable A2630 accelerator card? I know it operates modes (68000/68030) via software using r-mouse press on boot but that is pretty annoying to use. It won't even stay in 68000-mode after reboot. The board has jumpers mainly for setting onboard memory on/off but that's it which is not very useful.
-
I don't believe this is possible with the community's current knowledge and understanding of the 2630. Most accelerators with a disable function have it implemented in hardware, but the 2630 does it in software (well, firmware), so I think adding in a hardware switch is going to be complicated. The schematics are available if you're electrically inclined and want to investigate...
-
I kind of guessed so but I still had to ask :-[. Would be cool to have such a feature 8). Thanks for reply.
-
This isn't a very difficult hack or mod project. You need good soldering skills and the A2630 schematic. If you look at the schematic you will notice the PAL @ U305 has a signal called "68KMODE". This signal is asserted at a logical high state and negated at a logical low state. This signal is normally output from the Auto-Config register @ U303. This register normally comes out of RESET at a logical low state but can be changed to a logical high state by code in the A2630 boot ROMs.
So, if you disconnect the "68KMODE" signal from the Auto_Config register and connect it to a pull-up resistor and toggle switch to GND, you would then have a manual override circuit which bypasses the Auto-Config logic. ;)
-
Wow, thanks. I might give it a go some day when I have time. I guess I can't break the board with such wirings, huh? They used to make everything bulletproof back then ;)
-
I stand corrected regarding this being possible. Still beyond my technical ability, though. :)