Detecting presence of SD-card on HP-50g

[DavidM]

(07-15-2021 08:28 PM)ijabbott Wrote:  The SD card power and ground pins are designed to make connection before other pins on insertion, and to break connection after other pins on removal, so indeed power will be applied before the other pads are making contact if the calculator is on during insertion. (I don't know if that is actually a problem for the calculator.)

I was sure that I had read somewhere that the 49g+/50g should be turned off before inserting or removing the SD card. A quick look through the User's Manual for both of those devices doesn't seem to mention that, though. I still may have read it somewhere else, but that's where I thought I had gotten the info. So my memory is less accurate on this topic than the card currently inserted into my calculator...

Furthermore, after testing the above program with the card being inserted/removed without an intervening power cycle, it seems to still work as designed. Apparently the Kinpo O/S still knows when the card status has changed, even without a power cycle. So I'll amend the post to mention that stipulation may not apply after all.