fisher@star.DEC (Burns Fisher ZKO1-1/D42 DTN 381-1466) (03/20/86)
ihuin!tfilm asks: > 1. Are small computer 13 pin I/O ports all standard? No way. Sorry. > 2. If so, what is the standard? N/A 3. If not, what is Atari's standard? (Assuming we are talking about 8bit Ataris, now) Loosely speaking, the port is a serial TTL port which runs at 19.2 KBaud. It sends data in frames with an address indicating which I/O device, and with checksums, etc. It would be lots easier to use the Joystick ports on your Atari. These are 4-bit parallel I/O ports which use a standard peripheral interface adaptor chip (sorry, I don't remember the number). The normal mode of operation is to use them for input only for the joysticks, but it is relatively easy to toggle a bit in the PIA and pump bits out. Try such books as De Re Atari for details on all this. There is an article in Analog magazine within the past couple of years about constructing just such a thing as you propose using Shack parts. You might want to look it up. I'm going to try it one of these days. Burns ...decwrl!dec-rhea!dec-star!dec-fisher