I successfully tested all 6540 ROM with the Willem eprom programmer, a breadboard, 74LS14, machined socket and a lot of breadboard wires... Turns out one was bad, got glitches here and there when reading, it never verified correctly.
So, thinking if there's a neat way to test the 6550 RAM, both my eprom programmers can test some static RAM, I tried hooking up a pair (four bits to each) and test them as a 6116, wiring clock like when testing the ROMs and expected there to be problems - as I had no A10 hooked up - but best case I got errors on the second byte. Willem program starts by filling with $55 and $AA I guess it then inverts and reads back again.
Is there a handy layman's way to test the 6550 properly? Without using them in the PET (2001-8C)?
So, thinking if there's a neat way to test the 6550 RAM, both my eprom programmers can test some static RAM, I tried hooking up a pair (four bits to each) and test them as a 6116, wiring clock like when testing the ROMs and expected there to be problems - as I had no A10 hooked up - but best case I got errors on the second byte. Willem program starts by filling with $55 and $AA I guess it then inverts and reads back again.
Is there a handy layman's way to test the 6550 properly? Without using them in the PET (2001-8C)?
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