Author Topic: CPC464 Basic replacement eprom  (Read 417 times)

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Offline repetto74

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CPC464 Basic replacement eprom
« on: 21:14, 07 October 18 »
Hi Guys,


A fairly quick question on the eprom specs if I want to burn one and use it a a replacement for the Basic ROM on the CPC464. Is it a straight replacement pin to pin compatible? I heard about TMS eproms but does not know the detailed specification.


Thanks :D

Offline tjohnson

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Re: CPC464 Basic replacement eprom
« Reply #1 on: 01:18, 08 October 18 »
I'm pretty sure it is a 27c128 eprom you need.  Tms is a brand, Motorola I think, pretty much any will do.  I believe you could use a 27c256 no issues just put the code on twice in the upper and lower sections of the rom. I bought myself a Willem very cheap and after a bit of tinkering it seems reliable but requires a parallel port so no use on modern pcs.

Offline repetto74

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Re: CPC464 Basic replacement eprom
« Reply #2 on: 19:47, 08 October 18 »
Hi TJohnson,


Thank a lot :-). But what I do not understand is that I do find binaries of 16k and others of 32k size and I do not understand where the difference comes from  ::) .


From the CPC wiki the 40009 ROM is a 32K with both OS and BAsic so I assume that a 27C256 is needed here.


40009   32K ROM; BIOS and BASIC for CPC464 (English)

Offline tjohnson

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Re: CPC464 Basic replacement eprom
« Reply #3 on: 21:47, 08 October 18 »
Sorry I was talking Crap  I was thinking of the amsdos rom used in the 6128 which is a 16k rom.  The os/basic rom is indeed a 32k rom and therefore 27c256, easy to come by.
What are you trying to change?
« Last Edit: 21:54, 08 October 18 by tjohnson »

Offline repetto74

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Re: CPC464 Basic replacement eprom
« Reply #4 on: 00:03, 09 October 18 »
Quote
What are you trying to change?


Actually my CPC464 is working good but I was just wondering which eprom I do need to use in case I will have one day a rom failure :-). Actually I can also replace the original ROM with a programmed eprom and store it for preservation. Unless there is any BIOS enhancement which is worth replacing a good working original ROM  :D

Offline Bryce

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Re: CPC464 Basic replacement eprom
« Reply #5 on: 09:44, 09 October 18 »
The ROM is one of the less likely things to fail. As you've now worked out. The ROM image you need should be 32K and contain both the Firmware and BASIC, which have to match. ie: BASIC 1.0 will only work with the 464 Firmware, BASIC 1.1 only works with the 6128 firmware, but they can be used in either computer as long as they match.

Bryce.

Offline repetto74

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Re: CPC464 Basic replacement eprom
« Reply #6 on: 11:25, 09 October 18 »

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Quote
[size=0px][size=0px]but they can be used in either computer as long as they match.[/size][/color][/q]
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Hi Bryce,


So I can use both BASIC + OS of the 6128 with the 464?

Offline Bryce

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Re: CPC464 Basic replacement eprom
« Reply #7 on: 11:47, 09 October 18 »
Yes. It will give you extra BASIC commands such as circle and fill.

Bryce.

Offline repetto74

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Re: CPC464 Basic replacement eprom
« Reply #8 on: 15:03, 09 October 18 »
Nice to know that thanks  8) . I will for sure upgrade to the 6128 OS+BASIC  :)

Online Gryzor

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Re: CPC464 Basic replacement eprom
« Reply #9 on: 14:52, 02 November 18 »
Since we're at it, from http://www.cpcwiki.eu/index.php/Locomotive_BASIC :


Quote

The CPC implementation of Locomotive BASIC was developed directly from Locomotive Software's existing Z80 BASIC. The existence of this is cited as one of the reasons Locomotive requested that Amstrad change the CPC's processor from a 6502 to a Z80.


The 464 shipped with BASIC 1.0 on ROM.


The language was revised and debugged for the 664, 6128 and Plus machines to become BASIC 1.1. Changes were minor but significant for the programmer, and included:


DEC$ bug removed (in BASIC 1.0, it required two opening brackets and was undocumented)
Better handling of string arguments to RSXs (|DIR,"*.BAS" rather than a$="*.BAS":|DIR,@a$)
DATA statements can appear anywhere within a line; in BASIC 1.0, they had to be at the end of a line
FILL command (fill area with solid colour)
COPYCHR$ function (fetch character from screen)
Better garbage collection
Some number-handling bugs removed (e.g. in FOR loops with negative start/end values)
FRAME (CALL &BD19)
Extra, optional 'plotting mode' parameter for DRAW/PLOT commands (supported only through control codes on BASIC 1.0)
GRAPHICS PAPER, GRAPHICS PEN commands
ON BREAK CONT (disable ESCape)
CLEAR INPUT (flush keyboard buffer)
The AUTO command show the whole line if it exist, it only printed a * on the 464