exxos's Atari, Amiga & retro forum

Groppo91 wrote: 30 Mar 2022 14:39 Based on the schematics provided sporniket I am finding the Address pins wrong on my board:

Pin 2 says it should be going to A16 on the CPU (pin 47) but mine seems to be going to pin 48 which is A17.
I then tested pin 3 on ROM that should be going to A15 on the CPU (Pin 46) but mine seems too be going to pin 47 which is A16.

sporniket wrote: 30 Mar 2022 14:47

Groppo91 wrote: 30 Mar 2022 14:39 Based on the schematics provided sporniket I am finding the Address pins wrong on my board:

Pin 2 says it should be going to A16 on the CPU (pin 47) but mine seems to be going to pin 48 which is A17.
I then tested pin 3 on ROM that should be going to A15 on the CPU (Pin 46) but mine seems too be going to pin 47 which is A16.

If we are talking about p4 of my schematics ("U102 U103 - EPROMS"), the pin 2 of the eproms is named "A16", and is wired to "A16_SELECT" that goes to W104 and then connected either to GND or A17 of the address bus. So in fact all is normal on your board :)

stephen_usher wrote: 30 Mar 2022 15:15 You could always just swap the new ROMs over and see what happens. Wouldn't hurt anything... Just in case they were marked up incorrectly. :-)

stephen_usher wrote: 30 Mar 2022 15:15 You could always just swap the new ROMs over and see what happens. Wouldn't hurt anything... Just in case they were marked up incorrectly. :-)