There’s only one way to go and that’s forward ….

Not much happened with the project over the Christmas holidays .. we had a sad event in our house … my Mother-inlaw passed away on Christmas Day … she wasn’t your stereo-typical Mother InLaw thats for sure. We are going to miss her greatly but now she is with those who have gone before  …

Plans now are to split the efforts on two fronts …

 a) wire up the original SRAM portion of the IIcmxp prototype. This is all 5-volt stuff – just to prove that it works – I am pretty confident it will. I plan to possibly detach the AVR/CPLD/CF portion and glue that onto the development board pictured before.

b) carrry on with the development board and decide/work out how I will do the SDCard interface. ie with or without a CPU helper. I have been reviewing Alex Freed’s AVR, Verilog and 6502 code from the  Pseudo Disk  project to see how it ticks and to determine if I can re-use any of it for this project ( the ProDOS block driver portion that is not the 140K disk image part) . The alternative is to add a SPI Master port in the CPLD and interface that directly to the 6502  .. the kicker here is that there are only 4 i/o addresses available in the memory interface  A0 & A1 (to keep it compatible with the original memoruy expandable IIc. The IIc+ added A2 and A3)

I want the i/o interface to be as transparent as possible so that the RAM interface works with all previous software that used it. I need to determine how to piggyback the flash (SDCard Interface over top of that) I have some ideas which I have been kicking around for a while. I will document those in my next post. I would certainly welcome any feedback on that info when posted.

 Over and out


One Response to “There’s only one way to go and that’s forward ….”

  1. Nick Westgate Says:

    Sorry to hear about your loss. The Real Stuff in life can slow us down at times, but not forever …


Leave a Reply