Denyonet, megaflashROM scc+ and Padial SCMMC card reader: carts and social problems....

By stefA

Rookie (26)

stefA's picture

10-12-2012, 16:14

Dear all,
during the last monts I had the luck to acquire 3 lovely pieces of hardware:
1) a Denyonet from Sunrise (many thanks Rob!)
2) a LPE-MMC-V8 from Leonardo Padial (thanks a lot Leonardo!)
3) a megaflashrom SCC from MSXCartridge Shop (thank you!)
And I have to say that they are really cool.
But combining them on different MSX platforms I had peculiar results I'd like to tell you about.
When I use Megaflashrom+LPE on my nms8280 they are really happy to work together, but if I use the same combination on a sanyo wavy 70D the system randomly hangs (always very soon after the system boot)
When I use Denyonet+lpe on my nms8280 the system reboot over and over again always before basic or the msx-dos prompt, while if I use the same combination on the wavy the work in perfect harmony.
All the 3 different carts work perfecly on both systems when used alone.
MSXs are misterious machines....
Cheers
Stefano

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By Leonardo Padial

Expert (72)

Leonardo Padial's picture

11-12-2012, 16:54

How are you connet the All (the 3 different carts) alone ?. Whit one slot expander ? . Using the 3Th. internal slot ?.One custom cable ?.
Thanks.

By stefA

Rookie (26)

stefA's picture

11-12-2012, 22:34

Hi Leonardo,
no, I just use the carts two by two. Unfortunately I don't have any slot expander. The combinations (of two carts each) are:
1) LPE-MMC-V8 and Megaflashrom: this combination is ok on nms8280 but is really unstable on sanyo wavy 70D
2) LPE-MMC-V8 and Denyonet: this combination doesn't work on nms8280 (and on my 8250 also) but works perfectly on Sanyo wavy 70D
Regards
Stefano

By syn

Paragon (1937)

syn's picture

22-01-2013, 12:20

Any news or more info on these problems? I am thinking of unpacking and reconnecting my msx one of these days. The one I have is a sanyo wavy 70fd2, the same one as topicstarter but with 2 drives.

The problem is I am looking at various hardware options that I should buy, one of those options is padial sd card reader in combination with a megaflashrom scc, the combination that causes problems for the topic starter. So what I want to know is, what may be the cause of these problems, and are there other known incompatibilities? Anyone knows? Help is very appreciated.

By saccopharynx

Master (135)

saccopharynx's picture

22-01-2013, 14:43

Hi,

Stefano, I'm not an expert working with those cartridges and I don't even own a "real" MSX machine at presents days, but from my past experience and also from my personal projects I've been working on emulators, I could say that what you are experiencing is more or less common.

In my opinion, problems on MSX appear when combining several devices or applications that need a permanent (I mean fully resident) part in memory. As we know, the allocation of such sorts of programs can only be possible if they are allocated in page 3 (in case of a 64K machine). However, the free areas in that page are reduced since a substantial part is as well under possession of the MSX. When combining different elements, free space gets more reduced and finally the code from different applications overlap and then obscure things happen. As you said, "All the 3 different carts work perfectly on both systems when used ALONE."

Probably, if you could find technical specifications of the devices you're using, including the memory ranges used by them, you will see that some portions of RAM are shared. For instance, many times I've experienced similar problems with my own applications. They just worked fine but suddenly, after some changes on the computer configuration (but still the same machine), they stopped working. After doing some debugging, I found that vital parts of RAM where overwritten by other applications. For example, using MSXDOS-2 and a Sunrise interface to access a HD with only one FAT12 partition requires some RAM. But as soon as the number of partitions is increased, more memory will be necessary. So in that case, If you don't really know how MSXDOS-2 requests that memory in page 3 and you store your apps in there, problems are likely to occur. I think that the same drawbacks emerge when combining different hardware.

In the 80's, MSX computers weren't developed with massive combinations of hardware in mind. However, at present days, we just plug combos to keep them alive and interconnected, which of course cannot always be achieved without limitations.

S

By stefA

Rookie (26)

stefA's picture

26-04-2013, 11:27

Dear All,
thank you all for your kind answers. As you can see I wasn't really active in the forum during thees days, but let me say thank you saccopharynx: your explanation is a bit beyond my comprehension but the overall meaning is more than clear.
I'm waiting for my new MegaFlashROM scc+ SD, so be ready for my reports on new combinations!
Cheers
Stefano