The Sinclair QL Forum

Just browsing the 'net, when I came across a "ICL Mega OPD" pictures.

See https://fsck.technology/documentation/I ... er%20Desk/

As the QL ULAs are there, assuming it's later model of the OPD?

I have those pics/docs too. I think it was a model that never made it past prototyping/testing.

Hi,

My fault again.

I was given a much redesigned OPD by a software developer who lived in Cambridge. Tony Cheal. I found his name in a dump of an OPD ROM and took a leap of something and looked him up in the phone book for Cambridge. He was rather put out when I knocked on his door, I think he thought I wanted money for something, but once I explained my purpose he was very helpful.
He had been working on the OPD for use in the U.S.A. He worked on the code then sent it by OPD to the U.S. for testing. I think ICL were targeting the tele-marketing sector. The project was cancelled and he was left with all the kit. " Did I want it?" ....Yes please.
Sending files by OPD was a time consuming process. I once sent a 32k Rom dump to Murray in Glasgow and it took 32 mins. What it would cost to call the U.S. back then every day.............

The OPD was a big surprise using surface mounted chips and a giant daughterboard. Many changes.

In my write-up I had to call it something so it became Mega OPD. It's even that on Wiki .

David,

you wouldn't have any notes on how someone might add a UART device to the OPD by any chance? - documentation that survives in the public domain is a little sketchy - and I know of at least one interface with a UART device in it that plugged in via cartidge. It would seem to be a useul addition given the very slow speeds of the built in modem

Hi,

Spoiler alert *** I probably don't know what I'm talking about.

Do you mean something like the Asynchronous Comms Unit (ICL) or the Data Comms Adapter (BT)?

David

From Murray McCabe's web link (Binary dinosaurs)

https://binarydinosaurs.co.uk/Museum/ic ... riteup.php

It was these 2 that got my interest:

5.3 DATA COMMUNICATIONS ADAPTOR (DCU) - BT Reference 1887
This was provided for the Tonto by BT. It connects via a ROMPACK capsule slot,
is powered from the OPD and provides outputs (via a 25 way, female D connector)
which are compatible with RS232C, RS423 and CCITT V24 standards. Emulation of
the following terminal types is possible: DEC VT52 and VT100 (80 column mode
only) and IBM 3278 via a suitable protocol converter. Baud rates from 50 to 9600
can be configured from software. 2400 is the recommended rate.

5.4 ASYNCHRONOUS COMMS. UNIT (ACU)
The ACU was designed, by ICL, as part of the MEU expansion system and offers
speeds of up to 19200 bps by, optionally, by-passing the OPD's integral modem,
so allowing high speed communication and networking under control of one of the
terminal emulation programs. Canadian Standards and ULA approvals were obtained
and the unit was still available from ICL, in early 1988.
This unit's program is called a LOCAL COMMS. CONFIGUPATOR and allows profiling
of port parameters and operation by ACU or by modem. The ACU was designed to
compliment the MEU, was contained in a steel case approximately 4.5"x 10.5"x
1.5" and powered from the OPD, either direct from a ROMPACK slot or,
alternatively, it could sit on the MEU fed from that unit's 60 way expansion
port. The ACU 'footprint' is the same as the TELEDPIVE's.
The ACU has a single 25 way D connector, RS232C port based on an 'intelligent',
Intel P80C31BH processor with a 7.37280 Mhz crystal. A series of 74HCT257
multiplexers allow control to be taken over from the OPD, by the P80C31.
Firmware is provided in 2 EPROMs (a 27C256 and a 27C64). A small ASTEC
encapsulated SMPS is 5 powered from the +5 voLt rails to generate standard
RS232C port voltages which are not available via the ROMPACK slot (i.e. +12 and
-12 volts). Two 2K CMOS RAM ICs provide buffering for data.
Transmission and reception speeds can be specified separately in the range from
50 to 19200 bps. Other adjustable parameters are word length, parity, input and
output buffer sizes buffer filling and emptying levels, X-ON and X-OFF and flow
control.
Profiles/patterns for various port configurations can be set-up, stored in the
OPD PERMANENT STORE and recalled for particular applications

The top one - the DCU would seem simplest to re create

Hi,

I've got recent pictures of both units and their circuit boards.

Would they be of interest?

David

yes - that would be - A ROM would be even better

Many thanks David.

This is all very interesting information and useful for bringing the machine out of obscurity and making it useful.

If all this documentation etc. can be archived it would fill a void in the knowledge for the machine.

I must admit that I've not had time to try to generate a full set of manuals (especially the programming stuff) from the data dump I got at the beginning of the year. This would be necessary for any future program development.

As for a serial interface, if the programming interfaces for setting up interrupt vectors, device drivers etc. were known it wouldn't be hugely difficult to create a new serial interface using something like a Zilog SCC which could handle far higher speeds.

Hi,

My QL/QEP3 setup is rather cranky. I built up a library of images earlier in the year and borrowed a PC based programmer to get them all on to the PC. That had to be returned to Germany and it was delayed in Customs there for ages and was thought lost so I don't think I'll be doing it again.

I can do them on a QL disc if you can handle that.

Pics attached. I can do one of the underside of the DCA if needed

David