Greg Andrzejewski wrote:
I know there'd be a few people who'd like that upgrade.Good luck with the Vulcan firmware... It was written by none other than Bob Sander-Cederlof, and is quite interesting, IIRC. It did programmed I/O relatively quickly by aggressive loop unrolling. I took a look at it in the 1980s, and was surprised at its complexity and bank switching.Maybe it would be easier to write all-new firmware from scratch?
Don't count on it. I wrote a lot of firmware for AE products in the mid-80s and they used every trick in the book to keep parts count down. A large percentage of the Vulcan driver code is likely there to work around hardware weirdness.
One example: The Parallel-Pro buffer piggyback. This uses an 8051 family MPU to spool print output by serial bit-shifting through a "x1" memory architecture. To avoid adding hardware support for DRAM refresh we setup the on-chip timer to interrupt every 2usec and jump through an entire page of no-ops (in ROM) to twiddle all the address lines. Slowed things down some, but accomplished the goal of minimal hardware.
Steve