Primate: An APE/ProSys/SIO2PC/1050-2-PC Universal Interface For
Atari 8-bit

An infinite number of monkeys with an infinite number of typewriters...

Primate takes the place of both the SIO2PC type cable and the 1050-2-PC type cable for emulating peripherals and archiving floppy disks. It seemed strange to me that people would build two completely different cables for the task when they were both rather similar. I was also somewhat bothered by the so-called "one-chip" 1489 designs, as they relied on some cheap hacks to do their business. I have designed a one-chip circuit that acts as both types of cables (configurable via DIP switches). It is built around a MAX203 RS232<->TTL converter, mostly because that's what I had lying around. It could easily be built with a MAX232 or equivalent part (e.g. Sipex).

Primate gets its power from a PC's keyboard port when it's in 1050-2-PC mode. This is accomplished via a special inline keyboard cable much like the one supplied with the QuickCam. When in SIO2PC mode, it is powered from the Atari's SIO port. I salvaged the inline keyboard cable from an old peripheral. It beats using a wall-wart any day.

Not only is Primate configurable as to the type of cable (Atari<->PC or PC<->1050), but it also allows configuring the RS232 pins used for COMMAND IN/OUT. Some software uses different pins (e.g. RI is recommended for DOS APE, but DSR is recommended for WinAPE). Additionally, you can configure between DTR/RTS for COMMAND OUT when in 1050-2-PC mode.

You may say that having two separate cables is easier than changing all of those DIP switches. This is not true for me. I use the cable in APE mode more than I do in 1050-2-PC mode, so having to switch it over once in a while isn't a big deal. I considered making a nice digitally controlled version, but I don't use it enough to make it worthwhile.

The prototype was hand-wired and placed in a small project box. A high-resolution laser printed label was designed for the top of the project box. The artwork for the label is available here.

The collected works of Shakespeare...

[Inside Primate]
[Primate and 1050 Drive]

Primate is Copyright © 1999 Stephen S. Richardson. ALL RIGHTS RESERVED. APE/ProSys are Copyright © 1997 Steven J. Tucker. SIO2PC/1050-2-PC are Nick Kennedy's projects, and I don't claim to take credit for them.