I recently got a bunch of AT2864B EEPROMs that I am using to make multiplexer for a display.

I've hooked up all values correctly and looked through my code countless times without any trace of such bugs coming up (although I doubt it has anything to do with the programming in the first place).

I don't have an EEPROM programmer and I don't intend on buying one so if that is the only option I'm out of luck. I have however made a DIY programmer with an Arduino Nano and a single shift register (74HCT595) to cover all pins and added a way do disable the SDP on the chip. Whenever I have written my program to the EEPROM and tested it (no matter what I programmed to it), it acted very weird and since I practically have zero experience with non-digital electronics, I don't have a clue what is going on.

At first glance I would think it worked but whenever I put anything near to the chip it started dimming and brightening the display according to the distance between it and the chip. It is also not giving proper output values.

Has anyone had this issue before and do we know how to fix this? Have I maybe bricked it somehow or am I shorting something?

The display itself is a 4-digit 7 segment display with a common cathode where I added a resistor to stop the LED's from frying. The switching between displays is not the issue since I have yet to implement it and I am testing on a single digit. My other chips are TTL so naturally Vcc is 5V. I don't think there is anything to add here but I hope I can find a way to fix this with your help.

  • 3
    \$\begingroup\$ Show the schematics. Then show what you build. Either the problem is in the schematics already, or the circuit is not built according to schematics. The error may be very subtle \$\endgroup\$
    – Justme
    Jun 21 at 21:42
  • 1
    \$\begingroup\$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. \$\endgroup\$
    – Community Bot
    Jun 21 at 23:13


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