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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.

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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