On Jul 7, 2019, 3:26 PM -0500, Pasi Lassila <pasi.lassila_at_gmail.com>, wrote: > You can mix address pins together and data pins together and the RAM works the same. Some manufacturers don't even number the address or data pins since you can freely mix them. > > I made an SRAM board recently. I have it for sale at FB, Amibay and Lemon64. > http://www.amibay.com/showthread.php?106896-SRAM-for-C64&p=945376#post945376 > > During layout I enabled pin swap for the pins and this allowed for an easier layout. > > I also noticed Commodore swapped some pins. > > -Pasi > > > On Sun, Jul 7, 2019, 10:46 PM Jim Brain <brain_at_jbrain.com> wrote: > > > Memory in a 250466 PCB went flaky, so I tried my hand at repair. The PCB is the 3 ROM version, but with 4164 DRAMs. After desoldering the DRAMs, socketing, and installing some new DRAMs (all working now), I decided to see if I could switch the unit over to SRAM. It appears I and some other folks had similar ideas, as I see another project on Facebook to convert as well. I went a different direction and leveraged a small CPLD to do the conversion. After fighting last night with unsoldered pins, it is now working. > > > I decided to play around with the unit and map out the address pins. Interestingly, I find that MA6 and MA0 appear to be swapped on the PCB. I verified that MA6 indeed goes to MA0 on the 6567, though without a schematic, it's hard to trace MA6 (it goes through a '257, etc.). Anyone have a schematic? (Zimmers does not appear to have one) And, does anyone know if pin swapping was done on other versions? > > > > > > -- > > > Jim Brain > > > brain_at_jbrain.com > > > www.jbrain.comReceived on 2020-05-29 21:48:31
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