I've found a Z80 processor and a TC5564APL-15 8K static ram chips, and I want to test the RAM chip, because it's really old and I'm not sure that it's not damaged. I do not have any experience with Z80's and RAM chip's, I'm not even sure that I didn't damage it while desoldering. I found THIS forum link, where a guy wanted to use a different RAM chip, but the code looked OK and I've took it. I did some modifications:
- I only own one 74HC595, so I used that, I've connected the remaining address lines to 5V via 200Ohm resistors
- I did not use any capacitors.
- I've changed some connections.
Here's the modified code: https://pastebin.com/9nfTQY8X (Sorry for PB)
So it SHOULD print "0 0 0 8 / 0 0 0 8" to the serial, but it prints "0 0 0 8 / 8 8 8 8". The reason is unknown. Every other number works, I only found that specific bit not working correctly.
I'm not sure. Can my RAM chip be broken, or the circuit causes the problems?