How to test memory in an HP48 RAM card

[mfleming]

Hi all,

Hope someone might help with this question. After months of scanning TAS for a reasonably priced 128K RAM card for a 48SX/GX, I finally gave up and decided to make my own. Using plans from hpcalc.org and updating the BOM to a Cypress memory device, I managed to assemble a half dozen cards. Each one came up with the initial Invalid Card Data warning, after which I initialized by storing and purging a port variable (HP48SX). All seems well - I can store and recall variables, merge memory, and retain content on battery power when the card is removed from the calculator.

I wonder, does initialization test every byte of the memory on the card? Visual inspection indicates every pin is properly soldered. I'd just like to be sure all is well, and that I haven't left an address line floating or something.

Thanks,
~Mark