I managed to peel back the insulation and expose, then bend away the copper mesh that acts as a groundplane behind all forty of the signal lines in the ribbon cable. I could then trim it away leaving just the forty signal lines into which the vampire taps will connect.
|Copper mesh groundplane peeled away from signal conductor ribbon|
|Groundplane trimmed back leaving an area to connect press-on IDC connector|
|Clamping tool plus the two halves of the IDC connector|
|Connector on cable, ready to plug into the driver role extension board|
This cable gives a consistent 80 ohm impedance, important to handle the 3+ MHz signal generated to write clock plus data onto the drive. It must keep transitions within a 50 ns maximum interval, which is supported by high drive current and good termination.
I did work on the WriteSector logic and am preparing to run the logic analyzer to capture all the transitions I write, checking for a proper sector pattern. It will be painful, since what matters is the flip in state, not the absolute value of 1 or 0, and the relative timing of the flip compared to the 'clock' flips.
I will think a bit about how to best capture and test what occurs during the writing of a sector.