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Darn – what now!

June 11, 2014

This build is just a litany of fail! I had only done a bit of testing with the 2MHZ crystal but I’m *sure* I at least ran the blink sketch. I tried that at 4mhz and no go. Put the 2MHZ resonator back in and STILL no good.

It’s dead with Q on. I can verify memory and it’s ok.

I can load an assembly language routine that blinks the Q and it’s fine, even if I push it over several pages.

The problem seems to crop up if the 1802 itself writes then reads memory. The memory chip I have installed is a non-volatile ram. I’ll try the regular one.

Update:
Nope. Same issue with the regular RAM chip. So now I’m back to 2MHZ and standard RAM. The problem is pretty repeatable though so it should be susceptible to analysis. Write a little program that stays in page 0 and just writes/reads memory.

UPDATE: Aug 9 – I didn’t record what was causing this but I think it was undersoldered connections,

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