Flash- or SRAM-(EP)ROM expansions and their usage on the 6128plus

Started by GUNHED, 16:24, 01 February 22

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GUNHED

There are lots of expansions providing ROM for CPC6128 and 6128plus.
However some are not working with the 6128plus properly.
That's what I found:

Works well with 6128plus:
- Dobbertin EPROM card
- Britannia ROM plus
- Super Power ROM plus
- X-MEM - there seem to be problems when the ASIC is activated
- MegaFlash (if I remember correctly, but I will check again)
- M4

Problems with 6128plus:
- SYMBiFACE II
- FlashGordon
- Inicron ROM-RAM-Box

Now, tell us your findings. What is your experience?
(Why do I ask? Well, one never can't exclude the possibility the the source of problems is something else, so it's better to have more 'experience reports').
http://futureos.de --> Get the revolutionary FutureOS (Update: 2022.03.09)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

zhulien


Kris

Xmem is not fully compatible with Amstrad Plus, there is a conflict when ASIC is activated .


TotO

Most of the CPC boards have conflict with the Amstrad Plus i/o page, because it require to decode RMR2 to avoid that. There is a work around for the X-MEM and new programs to not unplug it. Use &7Fxx to access the external RAM expansion and &7Exx for the internal RAM expansion. So, you can use all the computer memory.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

GUNHED

Quote from: zhulien on 01:42, 02 February 22
don't forget m4 as working well with 6128+
Yes, right. The reason for not mentioning was that it is more like a 2nd computer, but I will add it to the list.  :)
Quote from: Kris on 08:35, 02 February 22
Xmem is not fully compatible with Amstrad Plus, there is a conflict when ASIC is activated .
Thanks for the update, I never had a problem with it here, but probably never got into that particular situation. (FutureOS for 6128plus uses hardware sprites and 4 MB expansion RAM, no problems).

Quote from: TotO on 15:51, 02 February 22
Most of the CPC boards have conflict with the Amstrad Plus i/o page, because it require to decode RMR2 to avoid that. ...
Yes, it would be great to have a positive list of expansions working 100% and working reliable, but with situations to omit.

Quote from: TotO on 15:51, 02 February 22
Use &7Fxx to access the external RAM expansion and &7Exx for the internal RAM expansion.
Using &7Exx for internal RAM is IMHO highly problematic when using more than 512 KB expansion RAM.
Here I have two CPCs with 4 MB RAM (one internal, one external). Also a X-MEM plus Y-MEM provide 1 MB of RAM. In addition the SF3 has 2 MB of RAM.
Therefore it would be better not to use &7Exx for anything else than the 2nd 512 KB RAM bank.

Maybe there is another way of working around. :-\
http://futureos.de --> Get the revolutionary FutureOS (Update: 2022.03.09)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

TotO

Quote from: GUNHED on 20:32, 02 February 22Using &7Exx for internal RAM is IMHO highly problematic when using more than 512 KB expansion RAM.Here I have two CPCs with 4 MB RAM (one internal, one external). Also a X-MEM plus Y-MEM provide 1 MB of RAM. In addition the SF3 has 2 MB of RAM. :-\ :-\
I'm speaking about a work around for the X-MEM on a Plus with program using the i/o pages.

Quote from: GUNHED on 20:32, 02 February 22Therefore it would be better not to use &7Exx for anything else than the 2nd 512 KB RAM bank.
With that feature, the X-MEM allow to access 512K + 64K on a 6128. So it is not exclusive to 512 + 512 RAM expansions. Anyway, a Plus program can easy check that usage.


Quote from: GUNHED on 20:32, 02 February 22Maybe there is another way of working around.
Unplug the boards? :-\
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

GUNHED

Quote from: TotO on 20:55, 02 February 22
With that feature, the X-MEM allow to access 512K + 64K on a 6128. So it is not exclusive to 512 + 512 RAM expansions. Anyway, a Plus program can easy check that usage.
Yes, that's a great feature. And it actually get's supported by my software.

However, if a programmer needs to do checking for a variety of expansions and situations, the program gets big and blown up with too much stuff.

And unplugging boards is no alternative, because I like the X-MEM very much!  :) :) :)
http://futureos.de --> Get the revolutionary FutureOS (Update: 2022.03.09)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

zhulien

Quote from: Kris on 08:35, 02 February 22
Xmem is not fully compatible with Amstrad Plus, there is a conflict when ASIC is activated .


I'm still not sure how they are incompatible

GUNHED

In the same way the M4 was, before firmware 2.0.7.
In case you bank in the ASIC memory mapped I/O, then this can impact on switching off the upper ROM...

However... in this thread I want to talk about expansions working or not. This means in case of X-MEM the functions are defined and know. It's not actually a bug, it's just a different way of working. But it's known how the expansion behaves, so it's ok so far.

The type of incompatibility I want to talk is different. For example I had an expansion (lets say it provides ROM) the it works a while, but suddenly crashed happen. The more the computer is running. After a while it's not possible to work, because there are too much crashes (they come from problems in switching between RAM and ROM). I actually did lot's of tests, which did lead me to the results provided in the 1st post.

Here it would be great to hear from you all about your experiences / problems / working-fine / whatever experiences with expansions at the 6128plus.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2022.03.09)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

PulkoMandy

Hi,


Could you elaborate on what problems you got with FlashGordon on AmstradPlus? I use this setup for a few years now without any problems, and I know a few other people who do.


The only issue I'm aware of is that a few of the early boards (serial numbers 00 to 09) were built with the wrong chips (74HCxx instead of 74HCTxx) and this creates compatibility problems with some machines and other expansions. If you still own one of these early boards, I can replace it with the current version that has no such problems.


If you mean something else, well... it would be nice to let me know, because now I have about 60 boards sent to various people and I hope I don't have to recall them all to replace them with a fixed version...

GUNHED

Indeed I had reproducible problems with the FlashGordon on the 6128plus. It runs well for 1-2 hours, but after that time sudden crashes start to happen. I assume this problem is coming from ROM banking. Maybe the switch between two ROMs or rather ROM or RAM creates issues. It's kind of hard to find out what actually happens.
The problem it not connected with other expansions, weak PSU or anything else which can be switched. If the 6128plus keyboard gets replaced by the 6128 keyboard the FlashGordon works perfect.


I will take a look at the 74H chips...
http://futureos.de --> Get the revolutionary FutureOS (Update: 2022.03.09)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

TotO

The C4CPC is the best to use with the Amstrad Plus / GX4000. Sure, the ROMs are stored on the SD Card, but depending of the usage, it is a must have device. More simple that using EPROM. ;D
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

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