That pesky Jupiter Ace *still* won't work...

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri May 30 17:37:00 2003

> I'm beginning to wonder... Does anyone know what clock frequency the Ace runs
> at? The RAMs I'm using are Toshiba TMM214APL-1 (2114L-2) chips. The EPROMs
> are Texas Instruments TMS2732s, part number TMS2732-45 -- 450nS rated. Is it
> likely that the Ace is acting up because the ROMs aren't updating their data
> outputs fast enough? By my reckoning, 1MHz = 1uS or 1000nS. 2MHz = 0.5uS or
> 500nS. ISTR the Ace ran at 1.8432MHz, which should still be in spec for the

This rather depends on how many clock cycles there are in a RAM cycle (or
more precisely, between the time the last memory control signal is
stable, and the time tha the data is read). This is not necessarily just
one clock cycle.

> ROMs...
> I've just checked the address lines going to the RAMs. I now have a list of
> which CPU pin connects to what RAM line. There are no shorts to Vcc or Gnd on
> the board, so I think I can rule out a bus conflict, unless the inputs to the

A short between 2 address or data lines? 2 chips enabled simultaneously
(address decoder problem)?

-tony
Received on Fri May 30 2003 - 17:37:00 BST