Baud rate

[MarkMLl]

I've just been taking a look at one of these and find that your 128k is somewhat on the fast side: I could get it working by adding 2 to the divisor but eventually iterated through the entire speed range and find that 124k appears to be the centre. This might obviously depend on the firmware version: I think that mine was 6.34 but it's just died on me.

The version that I've got here has a slightly different PCB, readily distinguished by English silk screening. It brings the microcontroller's Rx and Tx out to the USB data connections, but looking at the photos in your blog I suspect that yours does as well. I don't think this is particularly intended for ordinary users, since I think those pins are also used for ISP firmware upload.

There's obviously a possibility that the designers anticipated widely varying serial comms speeds, and that their own software progresses through multiple speeds until it recognises that distinctive sync byte at the start of each message.

My own humble implementation is at https://github.com/MarkMLl/shunda_tec06