ROM Help

[eight]

Hi there,

I hope I'm not imposing but I'm having a few problems and thought one of you might be able to help.

I'm trying to figure out the cartridge connector on the Wonderswan console. It's going ok, but I need to verify my findings. Unfortunately, most of the chips used in the carts are either Bandai customs or too difficult to find.

I don't have an exact number handy but a common example is:
MH8M16*****

I can't find the manufacturer and hence, can't find a datasheet. Does anyone have any suggestions on how I can go about finding the pin-outs? From those I can trace it back to the cartridge connector. I know which ones are connected to GND or Vcc, and have a rough idea of which ones are address lines and which ones are data - but I need specifics.

Sorry for the waffle , but if someone could help or point me in the right direction I'd be really grateful.

Cheers.

 

[nbucska]

have experience in reverse engineering but I have no idea what you are trying to do. Does the cartridge contain data or program ? Do you want to change it ? If program, for what processor ? <nbucska@pcperipherals.com>

 

[eight]

The cartridge contains data and program code for the Wonderswan games console (based around a custom i80186). I'm trying to figure out what each pin on the cartridge connector does.

Had the ROMs been standard off-the-shelf chips, I could have just traced ROM Pin 1 etc. back to the cartridge connector, and if that pin had been Vcc, then I'd know the pin it connects to is also Vcc. Obviously it's not always quite that simple but I've been making progress. My problem is that most of the ROM chips are not standard, so I can't pinpoint (excuse the pun) what the pins do.

Sorry if I'm not making myself very clear.

 

[jbartos]

Suggestion: If you happen to know how that connector looks, then visit

http://www.fciconnect.com/

for more info. They have many beautiful colorful pictures of connectors there.

 

[nbucska]

If you could access the 186 and make an adapter to the cartridge to access each line there ,too, it would be trivially simple to identify the lines. <nbucska@pcperipherals.com>

 

[eight]

>If you could access the 186 and make an adapter to the
>cartridge to access each line there ,too, it would be
>trivially simple to identify the lines.
I'm not entirely sure what you mean, but the CPU used isn't a pin-for-pin replica. It seems to be just compatible with the instruction set of the i186.

Something else I recently discovered was that the line I have named Address0 is not connected to any ROM chips in the cart, but it is connected to the RAM chips.

I don't suppose anyone has any idea why this might be?

Cheers.