24 Jan
2023
24 Jan
'23
11:47 a.m.
On 01/24/2023 11:09 AM CST Tony Duell via cctalk
<cctalk(a)classiccmp.org> wrote:
A couple of questions if anyone has experience of this machine :
1) There is a 5 pin DIN socket for connecting an external video
monitor. The signals seem to be TTL-level separate syncs at European
TV rates (15625Hz horizontal, 50Hz vertical) and separate (not
composite) 4-level analogue video.
I believe Philips sold a 12" monitor to connect there. What was the
model number? Is a service manual availabe?
Has anybody linked other monitors to that socket?
In the US in the late 80s and 90s, there were a crap ton of similar monitors (without
case) sold on the surplus market. I had one. I believe they were mostly Mitsubishi /
Panasonic. Most of them were 9" with a lesser number of 12". They had an edge
connector for the power, ground, H sync, V sync, and video inputs. Of course, in the US,
they were 15750 / 60 Hz sync. I can only guess what their original purpose was, but they
were easy to connect to a PC RGB video card (four resistors got you 16 gray shades.) So
that interface wasn't too uncommon. Perhaps there is/was something similar available
on the other side of the pond?
Maybe the reason you can't find any trace of the Philips add-on is for the same
reasons you suggest -- marketing realized it was of little value prior to releasing it.
2) There is a 50 pin card edge for a SASI interface. I
think the
Philips hard disk unit used the Xebec S1410 controller. I've
downloaded the user manual for that from bitsavers which at least
gives me the command set.
Does anyone have experience of a SASI-flash memory interface? Any
recomendations for things to look at? Or should I design my own, it
doesn't appear too hard?
I have an Ampro Little Board Plus, which is a single-board Z80 computer the size of a 5
1/4" disk drive. The "plus" means it has a SCSI interface. A couple of
years ago I was planning to build a flash disk for it and dug through a lot of specs and
bios code. Original SCSI was almost identical to SASI and they were often
interchangeable. The protocol is rather simple, as you stated. What I found in the Ampro
bios code was that for reading and writing only about 4 commands were used. Another small
number were used for formatting. I think, iirc, there were two types of read and two
types of write. I never got around to building the thing, but it should be pretty simple.
I would also be rather surprised if no one else has done it. But if you have the P-2000
bios code, you could take a look. I suspect it would be very similar to the Ampro code.
Will