2 May
2013
2 May
'13
11 a.m.
At 04:17 PM 5/1/2013, Tony Duell wrote:
There's two ROMs on the board, and the only recognizable number on that
Ah, that you didn't mention...
I've
opened up the drive. The external interface is to a "Data Path"
module that has a bunch of TTL and one large chip (40 -pin,
probably an
8031) with a Phillips logo. I think this is
confirmed to be an LMSI
rebrand.
I would not bet on it being an 8031, for several reasons.
The trivial one is that if it was from taht series, it would be more
likely to be an 8051 with an internal ROM. 40-pin chip is that "8031". However, you may
be right - week 31 of 1980
isn't unreasonable. And this is just the external interface card.
Actually, 1980 would be far too early for a CD-ROM drive, surely?
I've reassembled the drive as I'm about to
build a cable. It's clear
that it's a simple pin-for-pin twisted pair for the first five pairs on
the DA15. Tracing the connector on the drive shows me drivers on pins
1/9, 3/11, 4/12, 5/13 and receiver on pins 2/10. Tracing the
controller shows a receiver on 1/9, 3/11, 4/12, 5/13 and a driver on
2/10. It would take a rather evil engineer to mix those pairs up.
Certainly the exernal PC Philips/LMSI drive uses a straight-wired cable.
As well as the signal pairs, there may be a signal ground pin. I think
Philips used pin 8 for this. IF so, that should be linked as well.
-tony