Re: ssm aio interface

[David Wilson <mcs6502@gmail.com>]

On Feb 1, 11:05 am, linemand...@gmail.com wrote:
> and last night i found another 2e with an ssc so i dont need it for
> adtpro but id still like to find out the connector pinout.

If I had it in front of me I could work it out fairly quickly using a
multimeter (or even an RS232 breakout box with LEDs) and the A2
monitor.

1) Find the ground pin.
2) Measure the voltage on all the other pins.
3) Locate the two IO locations used by the 6850 and reset it into a
sensible mode.
4) write 00000010 to Control Register - this sets /RTS low
5) write 01000010 to Control Register - this sets /RTS high
6) repeat 4 & 5 until you identify the RTS pin
7) Find the TxD pin by writing a small program to continuously write
"U" which makes a nice alternating bit stream.
8) Once you have identified the output pins you can identify the input
pins by looping back one of them and seeing what the Status Register
reports.