avatar_Sebastian Blanco

Is a cpc464 using a 512k 100% compatible to the cpc6128 ?

Started by Sebastian Blanco, 01:52, 18 November 22

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Sebastian Blanco

The title says it all, I have a cpc464 and a 512k ram + floppy controller expansion from Zaxxon.
Using this the cpc464 becomes 100% compatible with the 128k cpc6128 software ?.



lmimmfn

6128 for the win!!!

eto

Quote from: Sebastian Blanco on 01:52, 18 November 22The title says it all, I have a cpc464 and a 512k ram + floppy controller expansion from Zaxxon.
Using this the cpc464 becomes 100% compatible with the 128k cpc6128 software ?.




I would say 99% 


  • Afaik Zaxxons device does not support the C3 mode for the bank switching. Very few software (like FutureOs) requires this.
  • Basic 1.0 vs. 1.1 as already pointed out

Except for that, I am not aware of any further differences


TotO

The Zaxxon expansion use DDI and dk'tronics cloned schematics, so it support C3 mode for all of the usages, while not running FutureOS in ROM. Now (unlike the X-MEM) it doesn't allows to use the system ROM of your choice, you will have to deal with your FW 1.0 and BASIC 1.0, making some programs not working. But not really a big issue, you are far more compatible than without it. ;D
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

eto

Quote from: TotO on 09:34, 18 November 22The Zaxxon expansion use DDI and dk'tronics cloned schematics, so it support C3 mode for all of the usages, while not running FutureOS in ROM.
Nice. I wasn't aware that Dk'tronics already has logic to implement that. 

What is different from a 6128 when it runs from ROM, so that the logic won't work anymore?

TotO

Quote from: eto on 09:54, 18 November 22Nice. I wasn't aware that Dk'tronics already has logic to implement that.
They are the first to sell since 85 the 64K RAM (256K in 86) expansions compatible with the Amstrad paging system that came with the CPC 6128. Because the CPC was originaly only supposed to have ROM on the expansion port, it was required to add one transistor to force the /MREQ signal for the RAM usage and a second transistor to force the A15 line to fake C3.

The issue is when you run a program from ROM that use the C3 mode, the &4000 memory is not properly paged, making always the ROM mapped instead of the RAM. The workaround is to disable the upper ROM (Gate Array bit from the RMR register) before accessing the RAM and restoring is next.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Sebastian Blanco

Cool, so is almost 100% compatible the zaxxon 512k + floppy drive also have a switch to enable parados, not sure if this is the same as using the 6128 rom ?.

Mostly my issue is. that I was lucky to found a 6128 locally and was thinking about if it deserved the time to get it up and running already having de cpc464+ram.

GUNHED

Quote from: Sebastian Blanco on 01:52, 18 November 22The title says it all, I have a cpc464 and a 512k ram + floppy controller expansion from Zaxxon.
Using this the cpc464 becomes 100% compatible with the 128k cpc6128 software ?.

No. Only Revaldhinos RAM expansion give you 100% compatibility regarding full support or RAM mode &C3. (Aside of the lower and BASIC ROM of course, for them you need a ROM card).

BTW: The dk'tronics 64 KB RAM expansion is only partially compatible the the 2nd 64 KB or ROM of the CPC6128. It lacks full support of RAM mode &C3 and also other modes needed for CP/M Plus. But CP/M Plus will run on the CPC464 with RAM expansion when it got patched.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

TotO

The CP/M patch is required if you do not have the correct CPC Firmware.
It is not related to the RAM expansion: https://www.cpcwiki.eu/index.php/DkTronics_CPM

About the FutureOS incompatibility, the subject has already been discussed.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

GUNHED

Quote from: TotO on 20:37, 18 November 22The CP/M patch is required if you do not have the correct CPC Firmware.
It is not related to the RAM expansion: https://www.cpcwiki.eu/index.php/DkTronics_CPM

About the FutureOS incompatibility, the subject has already been discussed.
Nice that you talk about FutureOS - because FutureOS love you and you all out there  :) :) :)
But please let's return to the topic.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
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 15:53, 19 November 22Nice that you talk about FutureOS
Because it is the exception that you are pointing through the 100% compatible. :-*
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Sebastian Blanco

I have some games that don't work Pinball Dreams will crash when you try to start playing and the logos at the intro that seem to use some kind of graphic trick are flickery.
Also "the abduction of oscar z" the colors are wrong is all red and black and some stuff don't show up.

TotO

Quote from: Sebastian Blanco on 20:17, 23 November 22Also "the abduction of oscar z" the colors are wrong is all red and black and some stuff don't show up.
What is the display you are using?
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Sebastian Blanco

Using a sony pvm-2010qm via scart, all the other games that y tried look great. This is the only one that have issues.

TotO

Quote from: Sebastian Blanco on 21:22, 23 November 22Using a sony pvm-2010qm via scart, all the other games that y tried look great. This is the only one that have issues.
Because this game don't properly sync the display. No patch was made since it was released.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Sebastian Blanco

Quote from: TotO on 21:28, 23 November 22
Quote from: Sebastian Blanco on 21:22, 23 November 22Using a sony pvm-2010qm via scart, all the other games that y tried look great. This is the only one that have issues.
Because this game don't properly sync the display. No patch was made since it was released.
Cool, so how is actually played ?. Only emulators ?.

andycadley

Old school CRTs are remarkably tolerant to timing being slightly off, the issues tend to arise when the same signal is fed into a more modern display that expects timings to be within spec.

TotO

Quote from: andycadley on 08:57, 24 November 22Old school CRTs are remarkably tolerant to timing being slightly off, the issues tend to arise when the same signal is fed into a more modern display that expects timings to be within spec.
That is not the issue here. The pvm-2010 is a CRT monitor. I was not able to display it properly on CRT TV. (not the topic)
-> https://www.cpcwiki.eu/forum/software-related/the-abduction-of-oscar-z-on-a-real-cpc/
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

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