Reprogramming FM receiver

[truffaldino]

Hello,

I am wandering if anyone tried to reprogram microcontrollers on FM 35/40 MHZ receivers. I would like to add some new functions to receiver and do not have enough space to put external microcontroller/wires and connectors. I have in mind Hitec micro revceivers that have PIC16F676 on the ouput "end".

Is it possible to do without special soldering equipment.

Truffaldino

[rich smith]

I've reprogrammed Corona RX which also use PIC. Not an easy job and did require soldering to download cable.

[Alan Hopper]

Truffaldino,
I reprogrammed a small hitec http://www.rcgroups.com/forums/showthread.php?t=765692 Not the easiest thing to solder but doable. You could probably make a fixture with sprung probes if you don't fancy soldering. I still regularly fly with mine programmed to decode Futaba pcm
Alan

[truffaldino]

Thanks a lot guys,

for info and very useful link!

Truffaldino

[Bruce Abbott]

For one-off programming of the HFS-05MS you can just tack-solder a few wires onto the board, but for software development it's better to install an ICSP header. I used a 5 pin strip of SIL turned pin socket. The connections were made with fine wire-wrap wire. I also inserted a 20k resistor in series with the PPM signal input to pin 15 of the 16F676 (RA0/ICSPDAT), because my programmer didn't like the external loading on this line.

I am providing my source code here even though it isn't quite finished, as it might be of some use to you. Although I have made several test flights without incident, please do not expect it to be bug free! Shift detect has not been tested so it probably doesn't work (not relevant on 35~40MHz).

[truffaldino]

Alan and Bruce,

Thanks a lot,

I have succeded to do all soldering without any special tools or probes, just using my very rough soldering iron and started firmare uploading/software development. Everything works so far.

Truffaldino

[truffaldino]

I am attaching PICBasic code as well as corresponding hex (firmware) file that works as original hitec firmware except gining servo pulse train on "B/CH6" pin instead of channel 6 of original version.

Thanks again
Truffaldino