Heathkit ET-3400

From: Doug Yowza <yowza_at_yowza.com>
Date: Wed Jul 8 03:16:24 1998

My ET-3400 is 99% on its way to living again. I found some 7-seg LEDs
that seem to work, and I've done some simple logic tests that check-out
OK. I still have no ROM for the thing, but that didn't stop any of the
old Altair hackers, so.... How hard would it be (for a software guy) to
replace the ROM with something else, say, a parallel cable from a PC that
fed data through the ROM socket?

The clock is already very slow, 500KHz, I think, but I could slow it to
1HZ if it would help. Could I software decode the address, do whatever
handshaking I need to do from the TTL-levels on LPT1, and emulate a ROM
without buying a ROM emulator?

-- Doug
Received on Wed Jul 08 1998 - 03:16:24 BST