HVC-VROM and SROM board for micromages

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crissaegrim87
Posts: 15
Joined: Tue Oct 06, 2020 5:51 pm

HVC-VROM and SROM board for micromages

Post by crissaegrim87 »

Hi, I was into make a micromages cart (also another with second quest), so splitted the ROM with FamiROM and burned 2764 for chr and 27256 for prg.
Then, soldered the 2764 and 27256 in the HVC-VROM-01 board but it didnt work, so opened another baseball game and the board was dip-24 for the chr (HVC-SROM-03).
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Comparing to a NROM, they differ, is a conversion posible?
Here is no mention to those boards: https://www.nesdev.org/NES%20EPROM%20Conversions.txt
And there is a pinout for chr in the SROM board: https://www.nesdev.org/wiki/Mask_ROM_pinout#Variants
Last edited by crissaegrim87 on Fri Jan 20, 2023 5:45 am, edited 1 time in total.
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: HVC-VROM board unknown

Post by lidnariq »

VROM is just NROM without the nametable configuration solder pads.
SROM is as described.
Both have a perfectly normal 28-pin pinout for the PRG ROM.
If you're having problems, it's not due to needing to do any patches - there's something else going wrong.
crissaegrim87
Posts: 15
Joined: Tue Oct 06, 2020 5:51 pm

Re: HVC-VROM board unknown

Post by crissaegrim87 »

Well, did a lot of testing in these boards, comparing to a proper NROM-256 of super mario bros. And guess what? pad 35 in VROM and SROM arent connected to A14 (pin 27 of prg eprom 27256). The track is missing!. And mirroring is hardwired (pad 18 is routed to pin 23 of chr eprom 2764). To anyone struggling with this, just lift pin 27 of prg and wire it to pad 35. The game is running now, very glitchy, but that is another story!

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crissaegrim87
Posts: 15
Joined: Tue Oct 06, 2020 5:51 pm

Re: HVC-VROM board unknown

Post by crissaegrim87 »

The game is running fine now, but I replaced the chr eprom due to oxidized teminals not stickig to solder
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