I've played with my programmer/ cable-clip a little tonight and quite frankly I lost confidence in this whole setup, let me elaborate.
First thing I noticed is that even though programer complains about mismatch after just a few bytes (like 1D), it actually programms the whole chip, just with almost every second byte being higher by 1 (like LSB being stuck high but only every second or fourth location) ?
Now is it happening during read or write is hard to determine, I know the programmer does work mostly fine using the zif socket, checked the cable/clip assembly a few times with a meter and they check out fine every time. I've programmed EEPROMS in circuit using this very clip mostly OK, (sometime it does error out).
I've jumped the CS2 to Vcc with 10 ohm resistor this time, the result is in the 2465A
usuthu65 written-read zip file.
I've also tried Mark's test program in both locations 2160 and 2260, the resulting reads are the same as for direct writes with my programmer.
I've actually went full medieval with
2465a_test_1 , found an ancient 27512, erased with UV eraser that hasn't been used for ~10 years, programmed and voilla!!
Unfortunately when it was all said and done, still "
TEST 04 FAIL 13 "
I thing I'm going to wait fot the dallas chip that I've ordered, should be here after the weekend, at least I'll have a guarrantee that I'm reading the memory right.
Could be that the actual SRAM is defective? We'll see.
Attaching also firmware dump from my scope.