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X-MEM, a new memory expansion for all CPC.

Started by TotO, 20:41, 26 April 14

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TotO

On the DK'Tronics boards, a big transistor force without problem the /MREQ signal needed to make a 464/664 working with a RAM expansion.
Do do simple, on the X-MEM, the CPLD is not enough strong to fight versus some Z80 clones.
So, it look that replacing the CPU with the Zilog one, solve that.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TotO

Quote from: gerald on 09:11, 04 September 14
I've got my notes  ;D

That a shame that AMSTRAD fixed the RAMDIS behaviour (so we don't need the force mreqn), but did not fix the C3 mode when in 464 configuration (and we still have to force A15).
But there is a simple solution to this : configure the pre-asic in 6128 mode so the XMEM work like on a 6128.
This need two wire soldering :
- one grounding the pre-asic configuration pin (tricky, 0.5mm pich IC) to switch to 6128 mode
- one preventing the non existing amsdos rom to be mapped in place of the basic one
Exactly, it was the conclusion and the better think to do. :D
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

arnoldemu

My games. My Games
My website with coding examples: Unofficial Amstrad WWW Resource

gerald

Quote from: gerald on 09:11, 04 September 14
But there is a simple solution to this : configure the pre-asic in 6128 mode so the XMEM work like on a 6128.
This need two wire soldering :
- one grounding the pre-asic configuration pin (tricky, 0.5mm pich IC) to switch to 6128 mode
- one preventing the non existing amsdos rom to be mapped in place of the basic one
Updated Arnold4 page with the modification : Arnold4 - CPCWiki

TotO

Are you sure that EXT pin must be forced to GND for making it working?
Isn't the DDI-1 task to do that?
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Bryce

Quote from: TotO on 12:11, 04 September 14
Are you sure that EXT pin must be forced to GND for making it working?
Isn't the DDI-1 task to do that?

I think that stops the CPC from crashing when no DDI-1 is connected.

Bryce.

gerald

Quote from: Bryce on 12:25, 04 September 14
I think that stops the CPC from crashing when no DDI-1 is connected.
Yes !

On a 6128, this one is also grounded (be it regular, cost down asic or plus)

The cost down asic include the DDI1 logic, which is active in 6128 mode. Leaving the Ext pin high will configure the DDI1 logic to map the AMSDOS as ROM0 like when you open LK1 in the DDI1.

TotO

OK. I have just expected that EXT was closed on 6128, only because it embed the FDD+AMSDOS ROM.
Now, if the pre-ASIC check that and the 464 don't have a DDI-1, it's better to link it to GND to always work. :D
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TotO

#383
I have sent a new Zilog Z80 to DerSchatten... And he already got it!  :o
After replacing the STElectronics by it, the Batman Forever and an other demo, now run on a pre-ASIC 464.

A random problem occur some time.
I suggest that is related to the expansion connector (need to be cleaned) or his own ribbon cable (need to be checked).

"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TFM

ROManager 1.87 for X-MEM and other released. For detail look here:
FutureOS corner

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TotO

#385
Dear CPC friends,

You are probably waiting your X-MEM... (or other boards from centpourcent.net)
You have to know that all boards was build!!! :)
But... The right angled MX4 connector is actually missing, so I can't ship them since 2 weeks!

Why? Because, I have ordered in Germany 1 month ago those connectors.
Printed in stock (as usual) I was informed that no stock is available since end of August.
In fact, the company order them in China to resell them to Europe. (not built in germany)

Now, I hope to get them as soon as possible... But, we can only wait. (me too, as I have sent my boards)
Thank you for understanding,

  TotO.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TotO

#386

The missing connectors are here. I will solder them this weekend and ship the boards next week!I remember you that a support page is available on CentPourCent [dot net] if needed. :)


"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Fernecho

#387
Hi all,
I introduce myself, I am Fernecho and I am a novice with the Amstrad CPC, I have a 464 and I've seen in this thread that the CPU STmicroelectonics Z80 give problems with  X-MEM MX4 and must be replaced by a Zilog Z8040004PSC.

Is a Zilog Z8400APS Z80 CPU 8614,  is a good CPU for work with the X-MEM MX4 ?, or should I replace it with the Z8040004PSC.



Greetings

TotO

I think yes, as CPC 464 V1 and V2 with Zilog CPU use this Z80400APS.
CPC 464 V3 and 6128 with Zilog CPU use the Z8040004PSC.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

radu14m


TotO

#390
All the X-MEM Boards are ready and the last will be shipped next week!  ;D
Please, peoples going to the ReSeT #18 event have to preorder first to be sure to get one.

"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Fernecho

Quote from: TotO on 12:23, 19 October 14
I think yes, as CPC 464 V1 and V2 with Zilog CPU use this Z80400APS.
CPC 464 V3 and 6128 with Zilog CPU use the Z8040004PSC.

Ok, thanks for your answer, I ordered a X-MEM MX4 a Mother X4 Main Board and also a Zilog Z0840004PSC to replace the CPU in case of problems.

TFM

Hit me! But IMHO it would be great if expansions would just work with the CPC without the need of changing the CPU.  :-X
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TotO

#393
Quote from: TFM on 18:59, 20 October 14
Hit me! But IMHO it would be great if expansions would just work with the CPC without the need of changing the CPU.  :-X
IMHO, it had been great if ST properly clone the Z80 CPU...  ::)
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TFM

Right, CRTCs are ever worse.


But that's how it is, and we have to life with it.  :-\
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TotO

Replacing a clone CPU with an original Zilog not conflict with "how it was", has there was used too.
On 100 X-MEM sold, only 2 peoples got the problem. And it was fixed like that.  :-*
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TFM

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TotO

"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

TFM

Is it known what in particular makes the problems? Probably it's some alteration of the timing of the clone cpu. I'm curious!
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

TotO

The DK'Tronics boards use strong transistors to won the bus-fighting against the CPU when running on 464/664.
The X-MEM CPLD does something close, but lose when it is an ST chip.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

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