MHROM ?

nintendo2600 · Post by **nintendo2600** » Thu May 21, 2009 9:43 am

Hey,

What can the MHROM smb\DH boards be used for? As in is it compatible with say CNROM or NROM by any chance? I got my hands on a couple
prom chiped smb\dh boards and I would like to put them to use. It was kinda neat coming across them as sooooo many are epoxy drops.

Cheers,

Shawn

Bregalad · Post by **Bregalad** » Thu May 21, 2009 10:00 am

MHROM and GNROM is an extension of CNROM which allow for PRG bankswitching. It is fully compatible with CNROM. In addition to that it's fully compatible with regular 27Cxxx EPROMs pinout.

tokumaru · Post by **tokumaru** » Thu May 21, 2009 10:30 am

I thought all SMB+DH carts used glop-tops... This is not the case then?

BootGod · Post by **BootGod** » Thu May 21, 2009 1:55 pm

Yeah actually they even managed to go thru 5 revisions of the normal MHROM PCB! A listing

Post by **Memblers** » Thu May 21, 2009 8:15 pm

Most of them are glop-tops, but you can tell which ones have chips because they have all 72 pins on the bottom.

The labels look different on the older ones, easiest to notice there isn't a "Seal of Approval" (oh noes!

). But those can have any kind of board inside.

I actually used MHROM for Garage Cart #1, however I used RAM for the CHR (needed a wire from the cart edge).

I may be remembering wrong, but the banking seemed able to use 128kB PRG (Nintendo's 28-pin one).

nintendo2600 · Post by **nintendo2600** » Thu May 21, 2009 11:02 pm

Bregalad wrote:MHROM and GNROM is an extension of CNROM which allow for PRG bankswitching. It is fully compatible with CNROM. In addition to that it's fully compatible with regular 27Cxxx EPROMs pinout.

Thanks for your response!

Bregalad · Post by **Bregalad** » Fri May 22, 2009 12:26 am

Also it seems European versions are never epoxy blob revision (the more common SMB/Tetris/Nintendo World Cup has epoxy blobs tough).

mark_k · Post by **mark_k** » Fri May 22, 2009 12:12 pm

Bregalad wrote:Also it seems European versions are never epoxy blob revision (the more common SMB/Tetris/Nintendo World Cup has epoxy blobs tough).

I'm not sure how common the blob version is compared to the DIP IC version, but at least some PAL SMB/DH carts have the epoxy blob board. One of the entries in BootGod's database shows it, and I have a UK version cart (label NES-MH-UKV) which uses that type of board too.

-- M

Bregalad · Post by **Bregalad** » Sat May 23, 2009 4:46 am

Oh forget what I said then.