Dumping special format rom

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Van NYYRIKKI

Enlighted (5588)

afbeelding van NYYRIKKI

08-07-2020, 21:03

This might be a little bit early, but I'm very hopefull that Takamichi can verify the last things soon.
Here is a summary of the whole thing that we have learned so that Manuel can start work on openMSX:

Silver Reed SRDS (GCMK-128X) cartridge HW summary:
--------------------------------------------------
Type: Custom 1Mbit MegaROM + SRAM
RAM: 4x32kB = 128kB
ROM: 2x64kB = 128kB

I/O port summary
----------------
Port 7:
Standard 8255 PPI control port. #81 is written here by software on boot.

Port 6 (Input, PPI port C):
Bit 0 = Memory card insert status (0=Card connected)
Bit 1 = Battery charge status
Bit 2-7 = Unused (return 0)

Port 5 (Output, PPI port B):
Not used

Port 4 (Output, PPI port A):
Bit 0-1: 32kB bank select for device (0-3), see bits 2-3
Bit 2-3: Device for memory area #0000-#7FFF
	0 = RAM (banks 0-3)
	1 = Memory card
	2 = Memory card
	3 = Graphics ROM (banks 0-1 in use, banks 2-3 return #FF)
Bit 4-5: Software ROM 16kB bank select #8000-#BFFF (=A14,A15)
Bit 6-7: Unused

Memory area #C000-#FFFF is not connected and therefore returns #FF

Unverified things:
- It is currently not known 100% sure if the battery status is straight or inverted, but when emulation is done original software should be able to tell that.
- It is not 100% sure that ROM dumps are in original order. The order is based on assumption that I/O port 4 bit 0 is connected to A15 on the Graphics ROM. On software ROM the assumption is that bits 0 and 1 are connected to A14 and A15
- It is not known how big memory card can be connected. Most likely limits are 32kB, 128kB and 256kB. During emulation development original software should be used to verify max supported size.

Here you can download both ROMs and image of the 32kB memory card.

Van Takamichi

Champion (361)

afbeelding van Takamichi

09-07-2020, 18:33

NYYRIKKI wrote:

I just wonder how big memory card this system supports... Does the manual say anything about that? In theory there would be enough space to support up to 256kB.

The manual doesn't say anything about the memory card size. It doesn't even state the maximum limit of saveable patterns. Whether "32KB" written on the card is genuine is uncertain. The full set of Knit Designer does NOT include the memory card, though it's illustrated in the conceptual diagram.
There are blue and pink (mine) memory cards but both say "32KB". Knowing the EC-1 electronic controller seems to be a superior ver, I read this page carefully but the card used there is same as mine.
Should I ask Silver Reed and Soft Byte?

Quote:

You should now see that first byte is 50, correct?

Yes, it's fine up to PO 4,0, but the the first byte is always 50 after PO 0,1/0,2/0,3/0,4 . The results look identical... if you are curious, here.
When I type PO 4,n instead of PO 0,n, the result is exactly as you described; 50, 51, 52, 53, full of FFs.

Should I test again WITH the card inserted, or is it dangerous?

My concern; foreword of the manual says "Portions Copyright 1987 ASCII Corporation" instead of usual "MSX is the registered trademark of ASCII". It might mean "Knit Designer is partially compliant to MSX standard".

Van NYYRIKKI

Enlighted (5588)

afbeelding van NYYRIKKI

09-07-2020, 19:58

Takamichi wrote:

The manual doesn't say anything about the memory card size. It doesn't even state the maximum limit of saveable patterns.

It might be that there was only 32kB cartridges available... When the emulation is running correctly, it should be easy to check if the software supports any bigger cards. ATM it is quite a bit more difficult to say as these page switching routines are really cryptic. There are tons of memory locations that are moved here and there and then the actual page switching is done by commands like OUT(C),E ... It might be that they intentionally tried to make it as hard to follow as possible to avoid piracy... Or then there is some bigger logic behind that just does not open to me. When we are able to add watchpoints to running program, it should be quite straight forward to see what the program does and what is doesn't do.

Quote:

Should I ask Silver Reed and Soft Byte?

I'm not too hopeful they would be able to help you with this even if they would like to. The card is anyway 30-years old and it is just luck if there is any documentation left... Although I must say that these kind of niche products usually have a lot longer lifetime than normal consumer software/hardware.

Quote:

Yes, it's fine up to PO 4,0, but the the first byte is always 50 after PO 0,1/0,2/0,3/0,4 . The results look identical... if you are curious, here.
When I type PO 4,n instead of PO 0,n, the result is exactly as you described; 50, 51, 52, 53, full of FFs.

Oh, great that you found my mistake and was able to correct it. Yes, this was exactly what I meant although I wrote wrong.

Quote:

Should I test again WITH the card inserted, or is it dangerous?

No, it is not dangerous, but I don't think we actually need to run any more tests. This all now seems to work how I documented it, so I think we are done. Thank you so much for your help! I think it was very nice from you that you were willing to send plenty of pictures, use your time and do all this testing with unfamiliar tools to get every aspect of this hardware documented.

Only thing that you can damage by doing more tests is content of the memory card... If that happens, you can restore it from backup by executing:

BLOAD"SUPER-X.LDR",R
_@
PO 7,81H
PO 4,8
L#MEMCARD.RAW,0#1
Quote:

My concern; foreword of the manual says "Portions Copyright 1987 ASCII Corporation" instead of usual "MSX is the registered trademark of ASCII". It might mean "Knit Designer is partially compliant to MSX standard".

To me it seems more likely that during development they used some development libraries made by ASCII and added the copyright notice just to be on safe side.

Van Takamichi

Champion (361)

afbeelding van Takamichi

10-07-2020, 15:10

Okay I won't do anything or query anyone for now. The card dump seems to follow certain pattern but I haven't looked much. The complex multiple ROM&RAM structure suggests the high retail price, knitting mums had been rich Smile2 I wonder how many are still using the KD.
There are so many unimaginable MSX applications, I won't be surprised to see MSX cooker or fishing rod Wink

Van Manuel

Ascended (16851)

afbeelding van Manuel

10-07-2020, 23:38

I'll start with it after the openMSX release and my holidays. Of course, anyone is most welcome to beat me to it.

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