HP 20b Sale in Germany

[Erhan]

Hello to all members,

thank you for the hint about the sale in germany. I have also picked up two 20b models which are arrived on saturday for me.

(03-09-2024 06:28 PM)SammysHP Wrote:  Unfortunately my attempts at flashing the firmware were not successful so far. I made a connector with pogo pins and a little PCB for the reset and erase buttons.

I have used a usb ttl adapter with a silicon labs chip in it, at least the drivers are from the website. I have followed the instructions "Flashing a WP34s using Arduino Nano.pdf" which is available on the source forge site. I have tried it with the figure one schematic but it didn't work at first. On the usb to ttl adapter the tx and rx lines are written on the silkscreen. After I switched the rx and tx line to the calculator pins I was able to flash the wp34s full bin software with the samba.exe application. It took about 17 seconds. Maybe you can try this as well.