lørdag den 16. maj 2015

Repurposing the HC-11 module

After playing with CC11XX based modules for a while, I noticed that the HC-11 was relatively cheap (~ 5-6 USD/each incl. shipping), came in a neat form-factor and had a co-microprocessor on board. It is intended to use as a wireless serial connection, but I figured it could be re-flashed, since the microprocessor on board is the common STM8S003F3P6.

Using continuity mode on a multimeter and the datasheet, is was clear that the two unmarked pads on the back of the module, exposed the programming pins SWIM and RST. I used a cheap STLINKv2 clone from eBay or DX to do the programming.

HC-11 with attached pin-headers

I cooked up a serial port connected spectrum analyzer, which was heavily inspired by the IM-ME implementation. The code is messy and my C-foo is weak, but play with it.

Use stm8flash to flash it. You might need to remove the read/write-protection. You can do that with the Windows-based programmer. I secured a USB-packet dump for it, so I might just make a small python-libusb script that replays that bit. Let me know if you need that.