Quick and dirty 41256 DRAM tester

I have an old PDP11 memory board with a bunch of 41256 DRAM chips that need testing. I was a bit surprise surprised at the lack of DRAM tester projects that I could find. I did find one based on a PIC, but nothing on an ARM/Arduino. So I built this…

It is basically a bread boarded Arduino UNO. The sketch runs four tests. The first loop loads all zeros in the memory and then will read them back. The second loop loads all ones. Loop three and four load alternate 1’s and 0’s.

There are three LED’s. The green LED will light until an error occurs. The red LED is dual function. If all four loops pass it will blink several times and then the four loops will repeat. If any of the loops fails only the RED LED will remain lit. The blue LED will light and stay lit if the first set of 4 tests passed.

Click on the images below to download the schematic and source.

Updated DRAM Tester

This is an updated design of my DRAM tester. This uses a 1284P avr chip. The Atmel studio project and schematic are included in this zip file. Running without the Arduino platform the timing is within sepcs of the dram.

AvrDramTester.zip

ChronWorks

Sun Jun 28 21:13:30 MDT 2015