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DIY data logger on HP48GX and Invalid Card Data message
09-15-2018, 02:45 PM
Post: #1
DIY data logger on HP48GX and Invalid Card Data message
Hello everyone,

I am new to this forum, at least as a member. It starts well as I already misplaced my first post in the wrong section Smile Sorry for the duplicate.

I am using an old broken 128 kB Klotz RAM card to make a kind of data logger on an HP48GX. I made a simple protocol to exchange data between the HP and a microcontroler soldered on the card in the P1 port and it is working ok, data can be transmitted and received by the HP. A simple application for example is a kind of multimeter where you can read a voltage and display the result on the screen.

My problem is that each time I turn on the calculator I have the message "Invalid Card Data" and this seems to trigger a warmstart. It is working well after that but this prevent me to run the data logger on a programmed alarm because if I do so the data logger program is not launched. I guess that this is due to the warmstart and instead of running the program I see 1 'data_log_prog_name' on the stack. I guess the '1' is the alarm index and 'data_log_prog_name' is the name of the program I wanted to run (specified as an <<action>> in the programmed alarm).

Do you know how it is possible to configure the card in the HP so to avoid the ICD message? Maybe with the CONFIG/UNCONFG instructions? I have read the section on cards in the great book of Gilbert Fernandes "Introduction to Saturn Assembly Language" available at hpcalc.org (section 66.1 and following) but I'm not very familiar with this instruction. How the HP48 discriminates between a valid card and an invalid one?

Does anybody has an idea on how to get rid of this warmstart?

Thank you!
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09-19-2018, 04:46 AM
Post: #2
RE: DIY data logger on HP48GX and Invalid Card Data message
I had a couple of 3rd party ram cards for my 48gx once. Not sure if they were Klotz, but they were too flakey. I'd bought them new, but they never worked well and I ended up just throwing them out.

I've never seen HP Ram cards for sale, but I haven't really looked too hard. Good luck!
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09-19-2018, 01:32 PM
Post: #3
RE: DIY data logger on HP48GX and Invalid Card Data message
(09-15-2018 02:45 PM)val_ Wrote:  ... My problem is that each time I turn on the calculator I have the message "Invalid Card Data" ... Do you know how it is possible to configure the card in the HP so to avoid the ICD message?

Have you tried the PINIT command? It solves most "Invalid Card Data" problems.

X<> c
-Joe-
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09-21-2018, 09:12 AM
Post: #4
RE: DIY data logger on HP48GX and Invalid Card Data message
Yes, I have tried the PINIT command but it doesn't fix the problem. I wonder how the HP test the card on port 1. How the calculator knows what type of card it is, 32 or 128kB for instance? Does the calc actually reads the memory on the card at the init stage or is it a matter of setting the appropriate voltage on few pins of the card?
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