Trying to find RC-20 commands
Well, I think the protocol description I've made is pretty much complete, now it's time to try every other command than the ones sent by the RC-10 and see what happens (by "see what happens" I mean "pray that the transceiver won't blow up"). I'll write a simple program on a Renesas microcontroller that will convert UART frames sent from my computer with Docklight into a synchronous "SPI like" data frame to the TM-241.
I'll try to update this entry ASAP with some test results.
10/07/2012: Well, after trying to use the R8C/25's integrated USART peripheral for days and a strong headache, I've finally capitulated and written a software protocol based on the Timer RA in "Pulse Width Measurement" mode. It uses the clock signal generated by the transceiver to send and receive data. That's the good news.
The bad news is that the transceiver doesn't seem to accept any command above 0x3F, so after all this hard work I still don't know how the RC-20 sends its commands, which is a little bit frustrating.
I did not waste my time anyway since I've found the purpose of some other bits from the LCD indicators bit field, but I would have liked to find more about the RC-20... I've updated the protocol specifications with my latest finds. I'm interested by any information about the operation of the RC-20 (yes, this is an SOS).