Another stupid flashing cable question HP-30b / HP-15C CE

[Maximilian Hohmann]

Hello!

(09-27-2024 01:21 PM)AnnoyedOne Wrote:  It would seem that is working but the download doesn't even though Samba thinks it does. I'd double check your connections (RXD/TXD reversed at one/both ends?).

As it can't get worse, I swapped the TX/RX cables and tried again. Nothing happendend, MySamba reported "No connection" as expected.

(09-27-2024 01:21 PM)AnnoyedOne Wrote:  The HP-15C CE firmware isn't protected (but could be) so the ERASE button just starts the bootloader. Reflashing and VoyagerSave work in XP/Win7 virtual machines (VM's) for me.

Flashing of the HP-15C CE was no problem at all. In my setup it worked only with Windows 10, but my only Windows alternative was XP.

(09-27-2024 02:09 PM)Eric Rechlin Wrote:  Since it completed the transfer, that tells me the cable is working fine. I can see a couple potential problems. The most common is that with the 20b/30b (unlike the 15c CE), I believe you need to hit Reset after flashing in order to start the calculator. Though with several battery changes since, you've probably already essentially done that.

I must have tried it 50 times by now with every possible sequence of Erase-Reset-On. It never worked as expected.

(09-27-2024 02:09 PM)Eric Rechlin Wrote:  The next most common is that you may have installed a version of the firmware not compatible with your calculator as currently configured. Specifically I mean installing a crystal version of the firmware without the crystal working. To test this, try installing the non-crystal version (you didn't specify which version you installed, so I assume it's the crystal version). If that fixes it, then double-check your crystal/caps and how you soldered them, make any necessary corrections, and then try flashing the crystal version again.

As I already had installed the crystal I tried to flash it with the "calc_xtal.bin" file. The result was as described above.
Today I took another new untouched HP-20b and attempted to flash it with the WP-31s software (my thought: less bytes, less chances for errors). Everything went as by the manual, but again, I only got the "Erased" display as before and no funcions at all.

The only thing left to try is to connect the Vcc line (jumpered to 3.3V) from the USB-serial adapter to the calculator and leave out the batteries completely. Maybe the common supply voltage will do some benefit?

Regards
Max