Most everything I've got planned involves the Atmel silicon onboard, the ATTiny 2313a.
The ATTiny is the (128 Byte) brains of this setup - it has a Universal Serial Interface which I am using as SPI. For the early demo, the first thing the board does is program the LTC6903 to get 2x VGA frequency (target: 25.175x2 MHz).
Most of the next work will involve the ATTiny. Here's the fun I've got planned.
- LTC6903 Frequency changing/tuning. (Hardcoded currently)
- Asynchronous Serial/UART control(!).
- SPI is great, but asyncronous serial is universal! If I say 8-N-1, you know exactly what I mean, right?
"Super Stretch" Goal
- World's smallest terminal emulator*! (I have 128 Bytes of RAM, plus the above needs to fit...)
- I called asynchronous serial a stretch goal when I started, but it's a real goal now.
Consider this my promise to you. Serial is a language that almost
everything electronic speaks - plus it'll be worth it for the "actually,
we've got that.." aspects of driving VGA over a serial port. And the
- (But, seriously, we have a black and white 80x60 mode - that only needs 4800 bits for a whole update. We can drive that with no problems, in theory...and it'll make a great demo that VGATonic is hitting its goals!)
- Maybe the smallest emulator, but since early teletype machines just printed out characters they could do it with barely any memory. Still - 128 Bytes.