Not much of an update, except that I got the first characters keyed from 1Keyer prototype. Here are two quick iPhone pics of it transmitting a repeat of the 'C' character (dah dit dah dit). The first is a scope trace of the keying output (normally would go to a BJT or an optoisolator) and the second is the sidetone output (which is generating a 700Hz square wave) that can be used as an audio indicator of the operation of the keyer.

Right now, I'm about 60 bytes over on total space used, and there were a few more features I wanted to add, and I haven't even really debugged all the features yet. 1K might still be challenging. I'd rather not resort to a lot of assembler tricks, but darn it, I will make it fit!