Sunday, January 8, 2017

Logic changes and new microscope put to use


My new emulator PCB arrived, now I am installing the components but I had to order a few I was missing. I also took the time to go over several of the production driver boards to make sure everything is good. This included removing and reinstalling some parts whose alignment I didn't like as they sat.

I picked up a Leica binocular microscope mounted on a boom, which is extremely helpful in dealing with surface mount parts, soldering and rework. It is very easy to check that connections are good. In fact, the narrow soldering iron tip is enormous in my field of view and the thin solder itself looks like a thick pipe.

New microscope checking out driver boards
I devised an entirely new way to handle the ReadClock and ReadData pulses, which does not depend on timing at all, and am implementing it. This also changed the logic to turn on and sync to the read heads, and needed tweaks for the logic that shifted data into the deserializer.

Hopefully this will solve the read errors, otherwise I may have to bypass the data separator function from the Diablo drive to produce my own clock and data pulses. I am still, even after another week of looking, exactly sure what is the root cause of the errors.

I also worked to repair an FPGA board whose mini-USB connector was defective. It had previously been removed and I soldered in a replacement today. The only problem was that a trace had been broken to one of the connector pins. I have removed the protective covering over a portion of the trace that remains and will have to solder in a bridge wire to finish this off. 

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