HP48G Connectivity Method in 2022

[TomC]

Well, again, this is getting more interesting/fascinating/frustrating.

I've tested:
Multiple Calculators
Multiple HP48/Serial Cables
Multiple PCs
Multiple USB/RS232 cables (both FTDI)

Same failure -

I cannot backup the calculator - as previously noted, the calculator displays ' EVAL STOP', and the Connectivity Software locks up. The Home directory of the calculator now contains a program object named 'fLaG' that contains a program that is obviously used to temporarily save the flag contents while the Connectivity code is running.

Perhaps some understanding of the connectivity code would lend some clues as to the failure mechanism here.

Again, connecting to and editing calculator objects works fine - it is only the 'Backup' feature that causes this failure - I would be curious if others have tried this feature when using the connectivity kit.

I'm starting to wonder if there may be some port settings in the properties of the COM port that needs to be fiddled with. (?)

Cheers!
TomC
ps: here's the fLaG object:
%%HP: T(3)A(D)F(.);
\<< 'fLaG' PURGE { # 40010400000FF0h # 0h } STOF
\>>

calculator

(09-18-2022 02:09 PM)TomC Wrote:  Hi Bob:

Thanks again for your attention.

I have verified that it is not the cable.

I've tried this with several machines and a couple cables. I'm using a modern 'gearmo' USB/RS232 cable with FTDI chipset)

(My interest is with HP48G and HP48G+, so RAMCARD is not an option.)

All other functionality of the connectivity works. It would be interesting to understand why the calculator shows an 'EVAL STOP' in the display and will not continue.

I have shut off clock display on the subject calculator. I tried a lower (2400) baud setting, but the Conn software insists that the backup be done at the highest communication speed.

I will continue 'fidgeting'.

TomC
ps: It is worth noting here that for cleaning contacts, one should avoid 'rubbing alcohol' as this has lanolin added. One should use the highest available strength of 'Isopropyl Alcohol' as this should not contain any additives.

(09-18-2022 12:56 PM)rprosperi Wrote:  Tom,

I've only ever had such (similar, not exact) problems with a single bad cable, is it possible yours is bad, or has loose/dirty contacts (on the 48 end more likely, as poor USB connection is typically audible from the Win10 machine). The tiny sockets in the cable are hard to clean but an old toothbrush and some alcohol and careful/patient poking into the sockets will do it. While you have cleaning stuff out, I'd also clean the metal pins on the 48 side, q-tips soaked in alcohol usually work best.

Another quite different approach for backup is to use a RAM card, it is much faster and more convenient, but of course is of no use if the machine is lost, etc. I've never had a machine crash affect the contents of a card's backup, and of course you should change the card batteries every couple years. NOTE that on a 48, when you change the batteries, you unintuitively must keep the 48 powered-ON while changeing batteries, as the 48 does not provide power to the cards when powered off.