OpenAmiga600RamExpansion icon indicating copy to clipboard operation
OpenAmiga600RamExpansion copied to clipboard
verified publisher icon SukkoPera

Data Lines switched

Open Avinitlarge opened this issue 4 years ago • 2 comments

HI Mr Sukkopera Ive noticed all of the Data lines are switched and don't follow the Amiga Schematic, D0-15 and UCAS/LCAS.

Avinitlarge avatar Sep 06 '21 14:09 Avinitlarge

You are definitely right, data lines and address lines are numbered incorrectly. I probably followed some random connector pinout I found online, but can't remember which one. For some reason I also crossed UCAS and LCAS, which luckily allows the expansion to work.

Thanks for the heads up, I will add a pointer to this issue in the docs.

SukkoPera avatar Sep 27 '21 10:09 SukkoPera

What should be fixed is the following:

  • The d0-d15 labels at CONN1 should be renamed according to the corresponding DRD0-15 pin they connect to (the latter is correct).
  • The de-scrambling of the lines won't be very significant per se, but it will swap the upper 8 data bits with the lower 8 bits, which means that the BCASL1 and BCASU1 lines must also be swapped, as they are crossed at the moment.

This is a lot of work and, since the two mistakes compensate for each other and the current board works wonderfully as-is, it is left as an exercise for the reader. 6c7c698 adds a note to the README pointing to this issue so that everyone is aware of it.

SukkoPera avatar Oct 19 '21 15:10 SukkoPera