Trying to get running an LSI 11/23

From: Eric Smith <eric_at_brouhaha.com>
Date: Mon Jan 3 18:10:57 2005

Tom Peters wrote:
> The bootstrap/terminator card had bipolar PROMs on it with a little
> charge pump chip to supply the -12 for the PROMs. But the chip wouldn't
> supply -12v soon enough after power up, so the system would drop to an
> _at_ debugger prompt instead of booting.

I think you must mean EPROMs. Bipolar PROMs don't need -12V; they run
on +5V only for read, and various voltages for programming. Early EPROMs
(before the Intel 2716 and TI TMS2516) needed multiple supply voltages
even for reading. Examples of multiple-power-supply EPROMs were the Intel
1701, 1702, 2704, 2708, National Semiconductor 5203, 5204, and TI TMS2716.
Received on Mon Jan 03 2005 - 18:10:57 GMT