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Dragon Scroll VRC2 translation

Posted: Fri Apr 29, 2016 8:54 am
by DamienC
I'd like to apply the fan translation of Dragon Scroll to my Famicom cart. I thought I found a few wiring guides online but they were for other mappers. Could anyone tell me the wiring/provide a diagram?

I'm probably going to just trace out the pins myself after work tonight and make sure they match the standard Nintendo 28 pin mask ROM, but a written guide would be a little easier.

Re: Dragon Scroll VRC2 translation

Posted: Fri Apr 29, 2016 11:00 am
by koitsu
All of this is on the nesdev wiki. The below information should be read, not skimmed.

VRC2 chip pinout: http://wiki.nesdev.com/w/index.php/VRC2_pinout

The official Dragon Scroll game appears to use mapper 23 -- this matters because there are multiple mapper numbers for VRC2 due to variance in layout changes (not chip pinout itself, just where the pins are wired):

http://wiki.nesdev.com/w/index.php/INES_Mapper_022
http://wiki.nesdev.com/w/index.php/INES_Mapper_023
http://wiki.nesdev.com/w/index.php/INES_Mapper_025

Dragon Scroll board details shows this is Konami board 350603: http://bootgod.dyndns.org:7777/profile.php?id=3802

In the VRC2 pinout wiki page, you can correlate that board with this statement:

Code: Select all

VRC2b, PCBs 350603, 350636, 350926, and 351179, mapper 23 submapper 15
   (fr) CPU A1 -> |03  38| -> PRG A15 (r)
   (fr) CPU A0 -> |04  37| <- CPU A12 (f)
But I would suggest tracing the CPU address line pins bare minimum anyway, just to double verify.

Re: Dragon Scroll VRC2 translation

Posted: Fri Apr 29, 2016 11:13 am
by DamienC
Thank you. I believe my copy is a VRC2b, but I'll double check when I'm home tonight.

Re: Dragon Scroll VRC2 translation

Posted: Sat Apr 30, 2016 7:21 am
by DamienC
Got it working. Traced all the pins out and they match the standard mask ROM pinout. It's a little flaky but I think that's because some of my soldering was a little rushed. I'll be fixing it later today.

For posterity:

Code: Select all

PRG

Lift pins 1, 2, 24, 30, 31, 32

Pin 1 (vcc) & 32 (vpp) to +5V
Pin 2 to Hole 24
Pin 24 to Pin 16 (Gnd)
Pin 31 float
Pin 30 to VRC2b Pin 39 (PRG A17)

CHR

Lift pins 1, 2, 24, 30, 31, 32
Pin 1 (vcc) & 32 (vpp) to +5V
Pin 2 to Hole 24
Pin 24 to Pin 16 (Gnd)
Pin 31 float
Pin 30 to VRC2b Pin 28 (CHR A17)