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?

closed as off-topic by user31481, per1234, gre_gor, jose can u c, Jot Nov 17 '17 at 1:37

  • This question does not appear to be about Arduino, within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • Add a capacitor (0.1 uF at least) to the RAM chip. – Mikael Patel Apr 1 '17 at 8:24
  • 3
    I'm voting to close this question as off-topic because it's about Z80 and old memory chips; no Arduino involved. – user31481 Nov 15 '17 at 21:04
  • The "modified code" on PasteBin has been deleted so there is definitely no way to answer this question as it stands. – per1234 Nov 15 '17 at 21:56

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