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Author Topic: MegaFlash and AMSTRAD 40051 IC  (Read 459 times)

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Offline jopil

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MegaFlash and AMSTRAD 40051 IC
« on: 15:40, 26 April 19 »
Hello.
I lately found & bought one more (3rd) of my first computers, an AMSTRAD CPC6128 but it is of a French * keyboard ROM on a 40051 IC. I have ordered some AT27C256 PROMS to burn and replace the French with the English BIOS 40025. Since for some many years now I'm on on the Cortex-Ms & Cortex-As platforms, I would need some help on how I'll locate this 40025 BIOS -filexxx.ROM and what else would I need, procedure-wise, to burn that filexxx.ROM on the AT27C256, apart from a programmer which I have. Also, is the MegaFLASH board of BRYCE still available around? Can I purchase one? Ready board or KIT? Thank you. jopil
* Keys on the French keyboard have been already modified to present the English keyboard layout.
« Last Edit: 15:53, 26 April 19 by jopil »

Offline Chinnery

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #1 on: 16:03, 26 April 19 »
I have some blank Megaflash PCBs - you can have one for the price of postage. However, finding the eeprom required may be a bit tough.

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #2 on: 18:02, 26 April 19 »
Thank you Chinnery. I checked at FARNELL, ARROW, DIGIKEY and W29C040P-90 is not available. You are right. After I'll locate it somewhere, or one full compatible to this one, and order it, then I'll let you know here for sending to me the blank MegaFlash, of which I thank you. If BRYCE could be of some help it would be great. Thankzzzz jopil
« Last Edit: 18:04, 26 April 19 by jopil »

Offline Chinnery

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #3 on: 18:21, 26 April 19 »
I've just checked on Aliexpress, and there are a few sellers on there with them in stock - generally around us$1.20 / piece.


Checking the pictures, I think I got mine from this here:
https://www.aliexpress.com/item/Free-Shipping-10pcs-lot-W29C040P-90B-W29C040P-90-W29C040P-W29C040-PLCC32-IC-In-stock/32868626166.html


[it may be a stolen picture though :)]


Offline Bryce

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #4 on: 15:16, 27 April 19 »
Hello.
I lately found & bought one more (3rd) of my first computers, an AMSTRAD CPC6128 but it is of a French * keyboard ROM on a 40051 IC. I have ordered some AT27C256 PROMS to burn and replace the French with the English BIOS 40025. Since for some many years now I'm on on the Cortex-Ms & Cortex-As platforms, I would need some help on how I'll locate this 40025 BIOS -filexxx.ROM and what else would I need, procedure-wise, to burn that filexxx.ROM on the AT27C256, apart from a programmer which I have. Also, is the MegaFLASH board of BRYCE still available around? Can I purchase one? Ready board or KIT? Thank you. jopil
* Keys on the French keyboard have been already modified to present the English keyboard layout.

Hi jopil,
you can find all the ROM images here: http://www.cpcwiki.eu/index.php/ROM_List
I don't make the MegaFlash any more, but there are several similar devices available (from ToTO for example) that offer the same functionality with additional features.
I may still have some W29C040 chips left over from back then if you decide to build one from Chinnery's PCB and can't find them anywhere else.
Bryce.
« Last Edit: 15:18, 27 April 19 by Bryce »

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #5 on: 21:17, 05 May 19 »
Thank you very much Bryce for your help. I'll give a try with  the AT27C256 and I'll let the forum know on the results within the next days.
John

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #6 on: 21:34, 05 May 19 »
Bryce, let me ask you one question:
The CPC6128 motherboard hosts the French "40051 / 32K ROM; BIOS and BASIC for CPC6128 (French)"
I will replace it with the AT27C256 (have already replaced IC with a socket).
Do I have to program onto AT27C256 both the OS_6128.ROM & BASIC_1.1.ROM? If yes, should I first program the OS and then the BASIC? Are there certain addresses that I need to point my programmer to for loading these ROMs onto the AT27C256?
Thank you,
John

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #7 on: 13:01, 06 May 19 »
Is it correct to load OS at 0x0000 and BASIC at 0x4000, or the other way around? Thankzz

Offline Bryce

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #8 on: 19:30, 07 May 19 »
Just patch the two files into a single file with the programmer software or a hex editor and program the EPROM in one go. The Firmware (Lower ROM / OS) needs to be first with BASIC in the second half of the ROM.

Bryce.

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #9 on: 01:47, 08 May 19 »
Thank you Bryce. That has been already done and actually the project successfully finished earlier today. At the following link, photos from the project are available. Didn't have to unsolder 40051, just cut the pins from their root on the IC and then very easily soldered the female pin-socket. Then AT27C256R was set in place. Regarding the 21 French keys EXCEL and laminated tapes gave a good solution. See photos. Thankzzz a-lot for your help. All the best, John
QUESTION: Firmware manuals clearly state that BASIC needs to always reside at 0x0000/Bank-0. How comes and in the PROM needs to be @ 0x4000 and not at 0x0000 where the OS_6128.ROM resides? Thank you


Photos Link: https://www.dropbox.com/s/gc1d6ahptvasgm2/project.zip?dl=0
 

Online TotO

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #10 on: 09:40, 08 May 19 »
Hello.
I lately found & bought one more (3rd) of my first computers, an AMSTRAD CPC6128 but it is of a French * keyboard ROM on a 40051 IC. I have ordered some AT27C256 PROMS to burn and replace the French with the English BIOS 40025. Since for some many years now I'm on on the Cortex-Ms & Cortex-As platforms, I would need some help on how I'll locate this 40025 BIOS -filexxx.ROM and what else would I need, procedure-wise, to burn that filexxx.ROM on the AT27C256, apart from a programmer which I have. Also, is the MegaFLASH board of BRYCE still available around? Can I purchase one? Ready board or KIT? Thank you. jopil
* Keys on the French keyboard have been already modified to present the English keyboard layout.
You was able to not hack your mainboard and only plug an external X-MEM with the good firmware (or advanced like 3.15) in example.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #11 on: 10:48, 08 May 19 »
Yes ToT0, check the photos. No need to unsolder any IC to be replaced. Just use a very-very thin cutter and you'll be able to remove IC while retaining the already very-well factory-soldered pins. You can then just solder the socket onto them very easily. John

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #12 on: 11:00, 08 May 19 »
OK. I have not seen the picture link!  ;D
May be a day if you come to a party, a french guy will be ok to exachange your QWERTY keyboard for your AZERTY one.  ;)
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Offline Bryce

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #13 on: 11:11, 08 May 19 »
QUESTION: Firmware manuals clearly state that BASIC needs to always reside at 0x0000/Bank-0. How comes and in the PROM needs to be @ 0x4000 and not at 0x0000 where the OS_6128.ROM resides? Thank you


I think you are mixing up the difference between the internal ROM addressing and the CPC addressing.

Bryce.

Offline jopil

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Re: MegaFlash and AMSTRAD 40051 IC
« Reply #14 on: 11:26, 08 May 19 »
Thank you Bryce. Maybe it is so as you say. Need to check a little deeper into 968-manuals. http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/memory-map/?action=dlattach;attach=14995 <-- this link helps. Also, Rodnay Zaks' "Programming the Z80" from my bookshelf make things clear. Thanks again.
John