Newbie - Dewoo CPC-400s. Memory prevents running MSX software

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By NYYRIKKI

Enlighted (5918)

Аватар пользователя NYYRIKKI

27-09-2015, 18:29

KURILSHIK wrote:

Is price 50$ а good?

Yes, for that price it is a deal unless the shipping costs end up being insane. Unfortunately I have also no any experience of shipping costs from Russia... Could you check some sort of estimation of local shipping costs to Finland?

Quote:

If I understand correctly, you are proposing to use an external cartridge additional memory (with mapper)? I do not have such. Unfortunately.
So I must do it myself. But, need circuit.

At the moment I see 3 workable options here...

1) You build a complete memory mapper and plug it in to Expansion bus.
Cons: Memory mappers need quite some logic & wires around them so this is not exactly easy fix... Is it worth the trouble is a question that you have to think your self. Few complete implementations can be found from here and here. Although Expansion bus is most _likely_ just normal MSX slot with wrong connector, this needs to be checked out as well before plugging anything in.

2) You buy a memory mapper from somewhere and build an adapter cable.
Cons: Expansion bus wires still needs to be examined first... There are 50 wires to connect...

3) You replace the RAM internally
This is what I've been thinking of... At the moment the computer is using DRAM, but my idea was to reuse part of the logic and add / replace existing memory with more easy to use SRAM. What I'm trying to figure out is that do we only need to add this one extra RAM chip or do we need some additional logic chips as well... and this all comes back to the /BUSDIR questions...

----------------------------

The more I read about BUSDIR the more confused I am at the moment. I think I'm starting to get the idea, but just in case could RetroTechie or Maxis please fill out this Yes/No question form:

1) As I don't handle I/O (because it is already handled by DW64MX1) I don't need to care about /BUSDIR ?
2) If I take the datalines from let's say MAIN BIOS ROM legs, I don't have to care about /BUSDIR ?
3) If I take the datalines from Extension bus connector I need to implement /BUSDIR ?
4) If I use /SLTSEL from Extension bus connector (or /SLT3) the /BUSDIR needs to be also connected to wire coming from Extension bus connector?
5) When /BUSDIR is needed, it is enough to connect /WR to /BUSDIR?

By RetroTechie

Paragon (1563)

Аватар пользователя RetroTechie

27-09-2015, 20:06

For the most part, you can ignore BUSDIR issues. You pick the /SLTSL in which you want your RAM, check in which direction the data buffer is switched when memory from that slot is read, and use that to decide where to pick up data lines.

Worst case, you take a guess and guess wrong. In which case you'll then have to pick up data lines from "the other location" to get things working.

Best case, you have a schematic and/or investigate existing circuit. In which case no guesswork is needed.

@Grauw: yes, an MSX memory mapper always occupies a single slot. And all 64K of it. Wink

By maxis

Champion (512)

Аватар пользователя maxis

27-09-2015, 22:55

NYYRIKKI wrote:

1) Although Expansion bus is most _likely_ just normal MSX slot with wrong connector, this needs to be checked out as well before plugging anything in.

Expansion bus on the back of the computer electrically is exacly the STANDARD MSX SLOT. The front slot is connected via
50 pin flex cable to similar connector on the motherboard.

@KURILSHIK
I'm curious about how did you buy this machine. When these computers were distributed in Moscow (and only there between 1992 - 1997), they were sold with the "adapted" classic games (free of charge) Wink
For example, the standard (so-called standard) .COM loader of Zanac-EX and the .DAT files were patched to work with the slot 0-2 memory.
So, in general, your CPC400 is an entirely normal MSX2 machine and all the classical tested software does work with it w/o any problem.

By Grauw

Ascended (10581)

Аватар пользователя Grauw

27-09-2015, 23:09

maxis wrote:

So, in general, your CPC400 is an entirely normal MSX2 machine and all the classical tested software does work with it w/o any problem.

Yeah, I think so too, I think there are any hardware modifications needed at all?

The problem seems to be originating only from running bad cracks. Just buy a MegaFlashROM SCC+ SD and run the ROMs with the environment they were originally meant to run in…

(p.s. When I try to run the CPC-400S in openMSX with Sunrise IDE or MFRSCC+SD, it boots to Basic and tells me Disk I/O error? Strange…)

By NYYRIKKI

Enlighted (5918)

Аватар пользователя NYYRIKKI

27-09-2015, 23:29

@maxis
We must have some different view of things... I think the machines you used might have also had an effect to what you today consider "all the classical tested software ". Anyway... in my head "adapted" + "patched" + "available from Moscow between 92-97" <> "w/o any problem".

By saying this I don't mean to put down local Russian communities that probably did a very good work there in adapting the games locally.

By NYYRIKKI

Enlighted (5918)

Аватар пользователя NYYRIKKI

27-09-2015, 23:32

Grauw wrote:

Just buy a MegaFlashROM SCC+ SD and run the ROMs with the environment they were originally meant to run in…

(p.s. When I try to run the CPC-400S in openMSX with Sunrise IDE or MFRSCC+SD, it boots to Basic and tells me Disk I/O error? Strange…)

Grauw, you are great! ROFL, can I now go and get my popcorn. Big smile

By Grauw

Ascended (10581)

Аватар пользователя Grauw

27-09-2015, 23:37

I know! I was hoping it was an openMSX issue… Smile Surely Sunrise IDE and MFRSCC+SD and MSX-DOS2 can handle RAM in slot 0.

To my understanding, the RAM in slot 0 issues arise mostly from software bypassing the BIOS, in stead implementing their own slot selection routines which manipulate I/O port A8H directly and do not do any subslot selection (necessitating the infamous poke -1,170, a hack which can only work when RAM is not in slot 0)… Surely the above mentioned don’t commit that sin?

By NYYRIKKI

Enlighted (5918)

Аватар пользователя NYYRIKKI

27-09-2015, 23:54

Grauw wrote:

I know! I was hoping it was an openMSX issue… Smile Surely Sunrise IDE and MFRSCC+SD and MSX-DOS2 can handle RAM in slot 0.

Well... There are other possibilities in this machine as well... The BIOS is quite a much hacked together and the disk ROM implementation is not perfect either.

Quote:

Surely the above mentioned don’t commit that sin?

Well... If you have the ROMs & openMSX in hand, changing the openMSX config would be quite easy to test.

By maxis

Champion (512)

Аватар пользователя maxis

27-09-2015, 23:57

NYYRIKKI wrote:

@maxis
We must have some different view of things... I think the machines you used might have also had an effect to what you today consider "all the classical tested software ". Anyway... in my head "adapted" + "patched" + "available from Moscow between 92-97" <> "w/o any problem".

By saying this I don't mean to put down local Russian communities that probably did a very good work there in adapting the games locally.

@NYYRIKKI Before the arrival of Daewoo, the only and only platform available was Yamaha, but mainly in public use. So all the "cracked" games were very badly adapted (absence of the official SW documentation) to run on only YAMAHA with or without MSX network. This is called "the classics".
So, when Daewoo was introduced, that was a shock for the local communities, since the most of the so-called "legacy" cracked SW didn't work at all. Hence, the groups of enthusiasts were working on hard to adapt the "standard set" MSX2 games for this machine.
Me personally, got the scans of MSX2 Technical Databook in 1990 (together with Egor), which was already quite late. Before we had almost no SW docs available (or some on MSX1).
See, KURILSHIK, IMHO, comes from virtually the same environment as myself and many other people. Therefore, he refers to the library of games, which are meant to run on MSX2 computer with the memory in the slot 3-2. Therefore, I've pointed out, that it is necessary to look up for the forum thread of Daewoo owners who still might have the SW cracks adapted for Daewoo. I do only own the KEYMASTER (as the developer).

By maxis

Champion (512)

Аватар пользователя maxis

28-09-2015, 00:00

Grauw wrote:
maxis wrote:

So, in general, your CPC400 is an entirely normal MSX2 machine and all the classical tested software does work with it w/o any problem.

Yeah, I think so too, I think there are any hardware modifications needed at all?

That is exactly my point too.
Regarding the CF controller, it will work 100% with Egor's BEER 202 or mine SuperATA. Since BEER202 is now emulated, you can give it a try.

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