External Memory Mapper

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Por usuario_msx2

Paladin (755)

Imagen del usuario_msx2

29-07-2009, 21:15

you have 3 x SCC !!
internal megaflash
external SCC+
SD +SCC

The 4mb mapper can be in an expanded slot ? ( i think so )

Internal megaflashromSCC (1scc)

if I use mmc reader with scc then will be 2 scc in use (more If I wish).

maximum 11 expanded slots (expanding slot 1 and slot 2)

Por Erikie

Champion (324)

Imagen del Erikie

29-07-2009, 21:18

Here is an image of the mapper. Could it be that I need to add a small cap (1000pF) to the highest address line? As was suggested for some mappers.

members.quicknet.nl/evanson/files/memmapper_small.jpg

Por Leo

Paragon (1236)

Imagen del Leo

29-07-2009, 21:45

>Doing Out(&HFC),12 then print inp(&hfc)
>(A) 140 (B) 12

--> This show a problem on 8220 : electrical ? timing ? false contact ?
it should report 12 as well on 8220.

>I have a NMS8220/00 (A) and VG8020/00 (B)
>Reading the ports FF, FE, FD, FC
>(A) 80, 81, 82, 83 (B) FF, 00, 02, 02

--> this shows that bios of 8220 initialize mapper while VG8020 does not.
the trick of pitpan could make VG8020 work, but sunrise says it works even
without. ?-)

>Last test of print hex$(inp(&Ha8))
>(A) without MM: F0 in slot 1: D0 in slot 2: machine did not work Have to check slot 2 >allthough FM pac did work in that slot
>(B) without MM: F0 in slot 1: D0 in slot 2: E0

-> F0 is ok without MM , slot 0 for page 0 1 = bios rom , and slot 3 for page 2&3 for RaM
when you put mapper in slot 1 we expect 50h = 01010000b but you get D0h 11010000b
the same for slot 2 we expect 10100000b = A0h but we get 11100000b
detecion of ram for page 3 seems to fail and bios seems to get back to slot3.

Question : does your mapper has a case ? I am asking because i think about the pins of
cart might not be very well aligned mechanically , if there is no case you can adjust it better
with your eyes ( i saw the case two times with my mapper + msx2+ panasonic and witha prototype card i have what i do i that i take care that pin1 and pin 49 are really centered )

about that 1000uF caps , maybe not stupid since you have problem with pages 3 and not page2 as if A14 was problematic but not A15.

btw i see the pin 1 & 3 quite used on bottom left of picture

Por Erikie

Champion (324)

Imagen del Erikie

30-07-2009, 09:10

Hi Leo, didn't you mean pin 2 & 4 on the bottom right side? Smile
And yes the mapper came in a huge casing. It is pretty hard to get and the sunrise CF and this mapper in a 8020 or 8220
The slots are so close together it barely fits
Still strange that the mapper works perfect in a 8250

Where should I look for putting that cap? on the MA14 or A14 address line?

Por Leo

Paragon (1236)

Imagen del Leo

30-07-2009, 09:57

i'd say on a14 , ma14 goes from register ls670 to ram , right ?

Does the cartridge ports work with normal games like megaroms ?

Por Erikie

Champion (324)

Imagen del Erikie

30-07-2009, 10:01

I will do some extensive tests this afternoon.
the vg8020 is my old machine and has not been used for ages. The 8220 I acquired with a lot of other stuff.
At least the FM pac worked in one of the slots on the 8220 Smile

As I have no schematic from this mapper I have no clue where ma14 goes to. I hoped that someone on MRC could tell me what kind of mapper this is. Will take me a lot of time to make a schematic of this mapper using a multi - meter Sad

Por Leo

Paragon (1236)

Imagen del Leo

30-07-2009, 10:37

well , we can see some decoding logic like 74ls138 or 7404 , i would not be surprised to find a 74ls32 .
There must be some 74ls257 for muxing addresses for dram (RAS/CAS)
On top of cart, we can see what looks like two groups of 44256 --> which makes 512kb , seems expandable to 1mb.
on the left there is the 670 which is the register bank for mapper register FC,FD FE FF .
the decoding for IO address seems ok , A0 - A7 seems ok.
...
I had a old msx2 hb700, i started re-using recently , it was not taking ROM games , or once evry 4 times. on the two slots.
i noticed one pin was very oxyded and a little moved , i have cleaned it and pushed a bit toward center and after many push/pull
the other slot started working ok, maybe just superficial oxyde .

Now it works better, well i have megaflash + SD v1.0 on it and nerver move-remove them.

Por HansO

Paladin (672)

Imagen del HansO

30-07-2009, 11:52

I will do some extensive tests this afternoon.
the vg8020 is my old machine and has not been used for ages. The 8220 I acquired with a lot of other stuff.
At least the FM pac worked in one of the slots on the 8220 Smile

As I have no schematic from this mapper I have no clue where ma14 goes to. I hoped that someone on MRC could tell me what kind of mapper this is. Will take me a lot of time to make a schematic of this mapper using a multi - meter Sad

I would not be surprised to see this mapper to be a variant of the Sony HBM-512 mapper:
http://msx.retro8bits.com/msxdocs/sonyhbm512sm.pdf

Por Erikie

Champion (324)

Imagen del Erikie

30-07-2009, 16:00

On both my computers (8020, 8220) it still does not work
inp(&ha8) still gives me D0 and E0
At least it works now in slot 2 of 8220

Por Erikie

Champion (324)

Imagen del Erikie

02-08-2009, 19:55

I guess my mapper is not working properly. It works in my 8250 with 2Mb internal memory
but not in a 8250 with 128Kb , nms8220 with 64Kb and vg8020 with 64Kb internal memory
what to try next?

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