3 Jan
2005
3 Jan
'05
10:10 a.m.
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
@ 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.