Hello! I was playing around with my PR-100A when I had an idea. The 100 and 300 series receivers are very similar, maybe they share hardware? After taking apart my PR-100A, I saw there were two more five pin ports for additional number wheels. The 100 uses two wheels, the300 uses three, and the 600 (and 400) uses four. After a bit of looking around, I saw it uses a PIC16F1938 micro controller which can be dumped with a PIC Kit programmer. After ordering, a bit of waiting, and a bit of soldering I got this.
I fired up MPLAB IPE and prayed that copy protection was not enabled as that would turn this from a $25 project to a $250-2500 project. Luckily it wasn't and I had a fresh HEX file.
The resulting file from my August 2017 manufactured radio is attached below (Changed from .hex to .txt so it would upload). As for the additional wheels, they are Hampolt model PF52 BCD switches soldered to five pin JST-ZH connectors. I will post more on these once they arrive to me so stay tuned!
Now here for the part I need help with. I do not own a R-300A and Com-Spec is no longer in business. To finish this project, I would need access to someone's R-300A to solder a few communication wires to so I can pull the firmware. If you will be at LDRS hosted by URRG this summer, I could bring the equipment to pull it there. Otherwise I would pay shipping for someone to send me a radio and back to pull the firmware. The soldering is all done to dedicated pads so there is little to no risk of damage to the radio.
I fired up MPLAB IPE and prayed that copy protection was not enabled as that would turn this from a $25 project to a $250-2500 project. Luckily it wasn't and I had a fresh HEX file.
The resulting file from my August 2017 manufactured radio is attached below (Changed from .hex to .txt so it would upload). As for the additional wheels, they are Hampolt model PF52 BCD switches soldered to five pin JST-ZH connectors. I will post more on these once they arrive to me so stay tuned!
Now here for the part I need help with. I do not own a R-300A and Com-Spec is no longer in business. To finish this project, I would need access to someone's R-300A to solder a few communication wires to so I can pull the firmware. If you will be at LDRS hosted by URRG this summer, I could bring the equipment to pull it there. Otherwise I would pay shipping for someone to send me a radio and back to pull the firmware. The soldering is all done to dedicated pads so there is little to no risk of damage to the radio.