Tokamac build and programming XC1736 chips

[DrGonzo]

Mind if I ask where you picked up the legit xc3030A? I'm still not convinced mine are counterfeit and still suspect issue(s) with my xc1736 and/or burning process, but I'd buy a few and swap them in to give it a try.

Thx!

 

[zigzagjoe]

@JC8080 sent me a Presto card that is supposed to work in a Color Classic. I've dumped the PROM.... drumroll, it's the same one! So whatever is responsible for working/not working in a color classic seems to be either a board revision (perhaps different color classic boards?) or component selection on the card.

Here are some pictures of the board in question.




Related, I have validated you can just dump these PROMs via a logic analyzer or even with a microcontroller (as I did). Given default OE/Reset polarity...

  SetVCC(1);

  digitalWrite(PIN_CE, 1); // cs = deassert
  digitalWrite(PIN_RESET, 1); // reset = assert / OE = deassert
  digitalWrite(PIN_SEREN, 1); // disable serial interface
  digitalWrite(PIN_CLK, 0);
  BitDelay();

  digitalWrite(PIN_CE,0);
  digitalWrite(PIN_RESET,0);
  BitDelay();

  int i = 0;
  while (digitalRead(PIN_CEO)) {

    Serial.print(digitalRead(PIN_DATA) ? '1' : '0');

    digitalWrite(PIN_CLK,1);
    BitDelay();
    digitalWrite(PIN_CLK,0);
    BitDelay();
   
    i++;
  }
  Serial.println();
  Serial.println(i);

This should result in the same number of bits as the PROM is rated to contain. To transform this to a binary dump, for each 8 bits, reverse the bits, then convert to a byte.

Given a bitstream from such a dump containing a series of bits like so: 0110001010101111
Split it into groups of 8 bits. 0123456789012345 -> 01234567 | 89012345
Now reverse the bits in each byte. 01234567 | 89012345 -> 76543210 | 54321098
Convert grouping of 8 bits into bytes, done.