And… after a long time testing, testing and waiting, I still haven’t a working TranswarpGS. Luckily I have solved the checkerboard problem.
But I now keep getting the ‘0301’ eror when powering up the IIgs with the TranswarpGS card installed. The ‘0301’ error means there is some problem testing the cache RAM on the daughterboard.
As I get the error with the board I got with the TranswarpGS and with a board I got from Henry Courbis (ReactiveMicro), the problem should be in the TranswarpGS card.
Trying to diagnose this problem with my BitScope Micro proved to be a pain, as I was missing a lot of lines to probe the signals. This meant I had to look for a more advanced logic analyzer. After searching for a while, I had the chance to buy one, a HP16500B with HP16550A Logic/State Analyzer card. This meant I had 96 channels I could probe!
But before I could start using the HP16550A, I had a lot to learn… What an advanced device.
Finally I had some working settings and I was able to follow the code run from the EPROM and I found the possible issue: The data returned from the cache card isn’t held on the databus long enough so the CPU can see it at the falling edge of ø2.
This means I might have some timing issues?
To be continued…