new guy understanding chips labels

Are you new to 6502, NES, or even programming in general? Post any of your questions here. Remember - the only dumb question is the question that remains unasked.

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ScarletDreamz
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Joined: Sat Mar 31, 2012 6:48 am

new guy understanding chips labels

Post by ScarletDreamz »

hey guys! since i already posted a trhead long ago trying to make some rockman 2 hacks to work on a normal console, i got a spare of Faxanadu and Megaman 2, and they have the same layout

Megaman 2:
Image

Faxanadu:
Image

i patched rockman 2 with the hack im going to use and it went to 267 kilobytes, i splitted the chr and pgr and this rom has no chr, but it had 11 kb char cuz of the hack maybe? and 256 kylobytes from the pgr, so since megaman only uses pgr beeing mmc1, does the hack rom make it use chr rom? btw im new to the chips and those stuff, i dunno iwch ones to choose, and dunno how to identify, but someone already told me, that i need a 2 megabits chip for the cartridge, so what i searched for 2 megabits 32 pins eprom ( since i think those are the ones i need to use) and i found some options,

i found an:
AMD AM27C040-90DC EPROM DIP-32PIN IC 27C040
an
AM28F020-200PC AMD 32-PIN 2MB FLASH EPROM NOS AM28F020
and a
AE29F2008-12 ASD 2M EPROM EEPROM Flash Memory W29C020C-120 29C020 IC

i also found some cheaps 27C020-15 27C020 Memory UV EPROM
Image

this one are the cheapest i found so far, would this one works whitout resoldering, since this ones are 32 pins, same as the megaman 2 and faxanadu cardtridges?

those three are 32 pins and 2 megabits i think so, and i was wondering, are they any cheaper? or even some cheaps, or maybe other models cheaper to use, because i didnt know they were like 8-15 us each one, so anyone mind giving me a help here, i really need to start working on it.

Btw, im worried about the rom hack since it made a chr rom of 8.5kb, do i need a eprom for it? or no, the pgr is 256, any help here please?

remember, you are talking to a totaly new guy, who dosnt know about chip prices, models and stuff.

i would also like to know if i could use the faxanadu copy to make the megaman 2 hack works.

if i use the last chips i wrote, what do i need to bend and sold with what, an iamge would be better if its not to much ._., like what to where and that stuff, im so new and im frustrated atm C:

thank you in advance ( btw sorry for my sucky english )
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rainwarrior
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Post by rainwarrior »

Maybe this article will help: http://www.callanbrown.com/index.php?op ... n-moai-kun

You will have the easiest time if your PRG-ROM chip is the same size as the original (I think you want the 256kb 27C020). Trying to use more than that will require a lot more work (extra parts, etc.).

Also, does the patched ROM you made actually run in an emulator? Rockman 2 uses CHR-RAM, so there should be no CHR segment in the NES file, and on the board you should leave its RAM chip where it is. Make sure your hack works properly in an emulator before proceeding, and try to get it to fit into 256kb.

And yes, Faxanadu looks like a suitable donor board for a Mega Man 2 repro.
ScarletDreamz
Posts: 8
Joined: Sat Mar 31, 2012 6:48 am

Post by ScarletDreamz »

rainwarrior wrote:Maybe this article will help: http://www.callanbrown.com/index.php?op ... n-moai-kun

You will have the easiest time if your PRG-ROM chip is the same size as the original (I think you want the 256kb 27C020). Trying to use more than that will require a lot more work (extra parts, etc.).

Also, does the patched ROM you made actually run in an emulator? Rockman 2 uses CHR-RAM, so there should be no CHR segment in the NES file, and on the board you should leave its RAM chip where it is. Make sure your hack works properly in an emulator before proceeding, and try to get it to fit into 256kb.

And yes, Faxanadu looks like a suitable donor board for a Mega Man 2 repro.
actually thats the guide i saw, but sadly someone told me that as a mmc1 is not that simple since i need to rewire some pins, since the pinout are diferent from a nintendo cartridge, so im looking what to wire with what
tepples
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Location: NE Indiana, USA (NTSC)
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Post by tepples »

You might be able to make it work by comparing the JEDEC pinout to the Nintendo mask ROM pinout seen here and matching the signals.
ScarletDreamz
Posts: 8
Joined: Sat Mar 31, 2012 6:48 am

Post by ScarletDreamz »

Ok.. so far i found out that
megaman 2 is SGROM wich is SNROM without the PRG RAM holes.
so i found out that:

this is for 27C64, 27C128, 27C256, 27C512, 27C010, 27C020, 27C040

SNROM (mapper 1):
Bend up pins 1, 2, 24, 30 and 31 (or cut tracks 2, 24 and 30)
Solder pin 2 to hole 24 (A16)
Solder pin 24 to GND (OE)
Solder pin 30 to hole 1 (A17)

and this is the eprom
---------------------------------------------
EPROM 27C020/27C2001 256KBytes (32pin):

---_---
VPP - |01 32| - VCC
A16 - |02 31| - PGM
A15 - |03 30| - A17
A12 - |04 29| - A14
A7 - |05 28| - A13
A6 - |06 27| - A8
A5 - |07 26| - A9
A4 - |08 25| - A11
A3 - |09 24| - OE
A2 - |10 23| - A10
A1 - |11 22| - CE
A0 - |12 21| - D7
D0 - |13 20| - D6
D1 - |14 19| - D5
D2 - |15 18| - D4
GND - |16 17| - D3
-------
i would love to know, wich one is the GND Hole, and that kind of stuff,

like where it says : Solder pin 24 to GND (OE) , GND the pin 16? or the hole 16?

since the megaman 2 game dosnt use CHR only PGR, this document

Image

its kind of consuffing since i dont know wich one to use to compare, the eproms? or the prg layout?
80sFREAK
Posts: 275
Joined: Sat Sep 03, 2011 11:40 pm

Post by 80sFREAK »

pin16 is kinda always GND, you can track it on PCB
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