Help with MMC1 Dev Cart

qbradq · Post by **qbradq** » Mon Mar 07, 2011 9:25 am

Let me first say that I know enough about EE to be dangerous

Can someone who knows a thing or two about this tell me if my plan is sound?

1. Purchase an Ultima: Exodus cart from a local reseller (there are plenty, and this game bites).
2. Purchase 512K Flash ROMs from Digikey (and a ZIF socket).
3. Purchase a TOP853 Programmer from Ebay.
4. Solder, cut and enjoy

What I am unsure of is this:

1. Is the flash chip I linked to compatible with the PROM in the cartage or will I need to re-wire it? I can't find any pinout info for that PROM.
2. Is the flash chip compatible with the programmer I found? I can't find any specific mention of the thing supporting Flash chips, but it's the same as EEPROM, right?

Part Costs:

Cart = $7.57
Flash ROM and ZIF Socket = $19.07
Programmer = $50.86
Security Bit = $6.72

Total = $84.22

Minus the programmer and security bit it's only $26.64 for the actual cart. Plus I get that programmer I've been threatening to buy for years

3gengames · Post by **3gengames** » Mon Mar 07, 2011 9:33 am

IIRC, that's SNROM->SUROM, right? Hehe. But here's pinout to Mask ROMS. Will need rewired.

http://nesdev.com/NES%20ROM%20Pinouts.txt

and some other stuff:

http://nesdev.com/NES%20EPROM%20Conversions.txt

http://nesdev.com/EPROM%20Pinouts.txt

Yay for the NESDev main page!

clueless · Post by **clueless** » Mon Mar 07, 2011 10:11 am

Although your plan is less expensive than what I am about to propose...

The following would be easier, as you won't have to cut + rewire any traces on the PCB:

http://www.retrousb.com/index.php?cPath ... ff7a188c42

1) MMC1 PCB = $9.00
2) Ciclone lockout chip = $4.00
3) Plastic case = $4.00, or take any case from any donor cart.
4) Two 6264 or 62256 SRAMs.

If you get your plastic case from retrousb, you won't have to buy a security bit. I bought a bit too (was cheap enough on ebay), but the bit's outside diameter is too wide to fit into the narrow slot on the cart. So I had to ship my bit to another nesdev member who ground it down and shipped it back to me. Pretty pricey proposition for piss poor plastics. (ok, that was really bad/lame...)

Its a trade-off between cost / effort / risk.

But now that I think about it, savaging an Ultima: Exodus cart might not be a bad idea, considering what is inside it for parts.

[Fixed SRAM part number --MOD]

qbradq · Post by **qbradq** » Mon Mar 07, 2011 12:02 pm

IIRC, that's SNROM->SUROM, right? Hehe. But here's pinout to Mask ROMS. Will need rewired.

http://nesdev.com/NES%20ROM%20Pinouts.txt

Thanks! I missed that link. None of the other documents specifically listed the 256KB chip. Looking at this there are a number of differences I will need to work around including cutting a few traces.

Posted: Mon Mar 07, 2011 11:11 am Post subject:
Although your plan is less expensive than what I am about to propose...

The following would be easier, as you won't have to cut + rewire any traces on the PCB:

http://www.retrousb.com/index.php?cPath ... ff7a188c42

1) MMC1 PCB = $9.00
2) Ciclone lockout chip = $4.00
3) Plastic case = $4.00, or take any case from any donor cart.

Yup, looks like that's what I am going to do. Just for fun I'll re-do the parts list and prices.

Cart (MMC1 PCB, CIC, Case) $23.00
Components (RAM, Flash ROM, Resistors, Diodes, Capacitors, Battery Holder, Battery, ZIF Socket) $19.70
Programmer = $50.86

Total = $93.56

Wow, that's only $9 more, it saves me a lot of re-wiring / re-routing, and as a bonus I get 32K of battery-backed WRAM. Yay!

Now that I think about it, I'll have 32K of CHR-RAM as well. Can I bank-swap CHR-RAM? I can think of a few compelling uses for that off-hand. Do any emulators support this?

clueless · Post by **clueless** » Mon Mar 07, 2011 12:16 pm

qbradq wrote: Wow, that's only $9 more, it saves me a lot of re-wiring / re-routing, and as a bonus I get 32K of battery-backed WRAM. Yay!

Now that I think about it, I'll have 32K of CHR-RAM as well. Can I bank-swap CHR-RAM? I can think of a few compelling uses for that off-hand. Do any emulators support this?

I don't see why not. Bank-switching char-ram gives you the benefits of both bankable char-rom (tile animation, like the water, tall grass and trees in Crystalis) with char-ram (can mix + match tiles + sprites limited only by storing them in char-rom and CPU bandwidth to push changes to char-ram during vblank).

qbradq · Post by **qbradq** » Thu Mar 17, 2011 7:42 am

Yay! I get to order my toys today!

I figured I'd give an updated parts list as it has changed some. Once I validate everything is working I'll post a very n00b-friendly DIY guide.

Supplier: RetroZone
Part: ReproPak MMC1 ($9.00)
Part: Ciclone IC ($4.00)
Part: Translucent Blue Case ($4.00)
Supplier Total: $17.00 + $6.00 S&H ($23.00)

Supplier: MCU Tools
Part: Willem EPROM programmer and USB Cable (optional) ($33.95)
Supplier Total: $33.95 + $11.00 S&H ($44.95)

Supplier: Futurlec
Part: 29F020 256Kx8 FLASH ROM ($3.50)
Part: 62256 32Kx8 SRAM (x2) ($5.00)
Part: 32 Pin Universal ZIF Socket ($8.50)
Part: Coin Battery Holder ($0.20)
Part: CR2032 Battery ($0.30)
Part: 0.1uF Ceramic Capacitor (x2) ($0.20)
Part: 1kOhm Resistor (x2) ($0.20)
Part: 1N4001 Diode (x10) ($0.20)
Supplier Total: $17.80 + $4.00 S&H ($21.80)

Project Total: $78.75
Minus Programmer: $44.80

I actually spent a little more than this to get better shipping from Futurlec. That is there only problem, the shipping is *very* high for UPS ($22).