Thanks for all the help as well as the great project. I've had a lot of fun with this.
I've tried to send the command string: 0xFE 0x4E 0x01 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07
Which should make a pattern whenever the ascii character 1 is written. The twatch accepts this command properly, and the C code seems to do the right thing, but all I can get is blank characters from this.
I'll post some photos of my twatch with the outputs. It makes a way cool clock, which alternately displays weather info.
I was wondering if anyone could get the custom character support to work. I've tried numerous things, but although the bytes I sent seem to be handled by the firmware, I don't actually successfully change the character generator.
I have some sample python code which tries. It also has the ability to write text to the twatch, and control it as a clock with weather report (via Google). I also built a nice wooden frame. If anyone's interested in the code I'll be happy to share it.