crtc

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Kev Thacker

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Mar 2, 1999, 3:00:00 AM3/2/99
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On Fri, 26 Feb 1999 23:23:50 +1000, fraser <fras...@flexi.net.au>
wrote:

>How do I know if my crtc (in my physical Amstrad CPC) is a crtc1 or crtc
>3 or whatever? Is it written on one of the chips inside and if so, where
>abouts is it?
Here is the legend:

HD6845S, UM6845 = type 0
UM6845R = type 1
MC6845 = type 2

Type3 is a big square chip inside CPC+ only.
Type4 ?????

Or, run Voyage93 or S&KOH demos and it will tell you.

If you've got a type 4 or a type 2, I am interested to try some
tests.

Kev


Peter Sørensen

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Mar 2, 1999, 3:00:00 AM3/2/99
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Type 4, presumably a big square chip inside the last batch of CPC
(non-pluses). Should be a ASIC type chip without the plus features.

--
Peter Sørensen
n...@kom.auc.dk

The solution to many problems lies in having somebody else do the work.
[Andrew S. Tanenbaum]

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Peter Sørensen

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Mar 3, 1999, 3:00:00 AM3/3/99
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fraser wrote:

>
> Kev Thacker wrote:
>
> >
> > Here is the legend:
> >
> > HD6845S, UM6845 = type 0
> > UM6845R = type 1
> > MC6845 = type 2
> >
> > Type3 is a big square chip inside CPC+ only.
> > Type4 ?????
>
> Ok, I've had a look inside and mine has HD6845SP so I guess it must be a type
> 0.

Yes, it is.

> For my next question, what's the big chip that's the same size as the Z80? It
> has AMSTRAD, 400109, 28527, 36 AA stamped on it.

It's the Gate Array. I guess its a 40010 type.

> There is a space for a
> similar sized chip printed onto the board just next to it waiting to be
> populated. What would go in this empty slot?

It's for a Gate Array of an earier type 40007 with at different pin
config.

Three types exists:
40007: used in early 464, needed a headsink.
40008: used in 664
40010: used in 6128

Cliff Lawson

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Mar 4, 1999, 3:00:00 AM3/4/99
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fraser wrote in message <36DD3809...@flexi.net.au>...

>For my next question, what's the big chip that's the same size as the Z80?
It
>has AMSTRAD, 400109, 28527, 36 AA stamped on it. There is a space for a

>similar sized chip printed onto the board just next to it waiting to be
>populated. What would go in this empty slot?


That chip is the "gate array" that contains all the "glue logic" that ties
the main components of the CPC together. The very first 50 prototype CPCs
had a gate array simulator board (GAS board!) and that connected to the main
board through that empty connection site to make a sort of two board
sandwich. There were about 40-50 TTL packages on that GAS board and they are
all contained within the gate array.

Cliff, Amstrad
=======================
mailto:cla...@amstrad.com
http://www.amstrad.com
http://cliff.lawson.net
=======================

Peter Sørensen

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Mar 4, 1999, 3:00:00 AM3/4/99
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Cliff Lawson wrote:
>
> fraser wrote in message <36DD3809...@flexi.net.au>...
> >For my next question, what's the big chip that's the same size as the Z80?
> It
> >has AMSTRAD, 400109, 28527, 36 AA stamped on it. There is a space for a
> >similar sized chip printed onto the board just next to it waiting to be
> >populated. What would go in this empty slot?
>
> That chip is the "gate array" that contains all the "glue logic" that ties
> the main components of the CPC together. The very first 50 prototype CPCs
> had a gate array simulator board (GAS board!) and that connected to the main
> board through that empty connection site to make a sort of two board
> sandwich. There were about 40-50 TTL packages on that GAS board and they are
> all contained within the gate array.

Do any of those CPC's exists today?, any change of a picture/wiring
diagram of the board?

How was the GA designed at that time, e.g. was any computer tools,
simulations etc. used?

About the ASIC of the PLUS, was that one designed in VHDL, Verilog or ?,
where can I download the code ? ;-)))

Cliff Lawson

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Mar 5, 1999, 3:00:00 AM3/5/99
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Peter Sørensen wrote in message <36DEE0F2...@kom.auc.dk>...

>Do any of those CPC's exists today?, any change of a picture/wiring
>diagram of the board?


The fifty grey prototypes? No I fear they have all been junked long ago. I
guess it's possible that Loco or MEJ may still have one as a "souvenir" but
all that old junk (and a few other intersting things such as the Ant
prototype were just thrown out from Amstrad a long time ago. The majority of
the grey prototypes were given to software houses to start producing some
games pre-launch which is partly why the CPC was successful as it did have
quite a few titles available at launch but those machines were (on the
whole) kept by the s/w companies concerned.

>How was the GA designed at that time, e.g. was any computer tools,
>simulations etc. used?


Not sure as it was done by MEJ but I'd imagine it was just done using a
normal CAD program rather than a specific GA design tool as it was a very
new technology at that time.

>About the ASIC of the PLUS, was that one designed in VHDL, Verilog or ?,
>where can I download the code ? ;-)))


Not sure, I think we still have the tapes for the Sun workstations somewhere
but I dunno what design system Steve Gane used to design that chip. You most
certainly cannot download the data as it is very definitely Amstrad's
copyrighted material!

Cliff


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Kev Thacker

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Mar 10, 1999, 3:00:00 AM3/10/99
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On Tue, 09 Mar 1999 22:08:00 GMT, da...@altavista.net wrote:

>>Cliff Lawson wrote:
>>>
>>> fraser wrote in message <36DD3809...@flexi.net.au>...
>>> >For my next question, what's the big chip that's the same size as the Z80?
>>> It
>>> >has AMSTRAD, 400109, 28527, 36 AA stamped on it. There is a space for a
>>> >similar sized chip printed onto the board just next to it waiting to be
>>> >populated. What would go in this empty slot?
>>>
>>> That chip is the "gate array" that contains all the "glue logic" that ties
>>> the main components of the CPC together. The very first 50 prototype CPCs
>>> had a gate array simulator board (GAS board!) and that connected to the main
>>> board through that empty connection site to make a sort of two board
>>> sandwich. There were about 40-50 TTL packages on that GAS board and they are
>>> all contained within the gate array.
>>

>>Do any of those CPC's exists today?, any change of a picture/wiring
>>diagram of the board?
>

>I'm sure I saw a 464 in a differently coloured case at an All Formats
>Computer Fair a couple of years ago. Would that have been one of the
>prototypes?
Was it a grey colour? I've seen a picture of the grey coloured one
in AA, and I think that was a prototype. Cliff can you confirm?

Kev


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