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how to burn 8 mbit rom to 32 mbit eprom

Posted: Sun Jun 14, 2020 7:03 am
by kataklysm101
Hi, i have question like in topic. I'm will try to find information about burning 8 mbit rom (zelda in this case) to 32 mbit eprom (27c322).

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Sun Jun 14, 2020 1:38 pm
by tepples
The NES and Super NES use an 8-bit data bus. The 27C322 EPROM, by contrast, is designed for a 16-bit data bus. I don't know what board you're using, or whether or not it has a multiplexer, but you might need to follow each byte of data with a byte of $FF so that the other 16 bits are occupied. This gives a 16 Mbit (2 MiB) file. Double it up (the same file twice in a row) to produce the 32 Mbit file to record on the EPROM.

Some circuit boards are specifically designed for connecting a 16-bit EPROM to a computer with an 8-bit data bus. They contain a set of eight 2:1 multiplexers to select the low or high 8 bits of each 16-bit word that the EPROM outputs. For these, you just write the whole ROM four times in a row.

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Sun Jun 14, 2020 3:03 pm
by kataklysm101
Hi, thanks for reply.
I was make board adapter nad use a donor cartridge, the adapter is from this site CLICK this is connection board for this Image

Im try to burn rom first time and i have willem programmer with adapter for 27C322. Can you tell me how to prepare rom in good way ?
another question is what kind of file i should burn ? *smc *sfc ? my rom oryginally is smc. Willem can programm it with 16 bit mode (word mode).
I was try to burn my file today but i have error at end of burning (0xFF)

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Sun Jun 14, 2020 7:00 pm
by poorstudenthobbyist
Not sure what your error is, since I don't use a Willem programmer, but your file extension is fine.

That table from my website isn't how to wire the program adapter, it's how to wire the 27C322 to the SNES board after you've programmed it. You want to follow this page instead.

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Mon Jun 15, 2020 1:36 am
by kataklysm101
poorstudenthobbyist wrote:
Sun Jun 14, 2020 7:00 pm
Not sure what your error is, since I don't use a Willem programmer, but your file extension is fine.

That table from my website isn't how to wire the program adapter, it's how to wire the 27C322 to the SNES board after you've programmed it. You want to follow this page instead.
Very thanks for reply :) i'm study Your website for several days, i'm know it's a table for adapter for a donor cartridge and i was make one. All problems what i have is what prepare file with right way and programm EPROM, so i have questions for "Retro game professor" :)

1. does the file i prepared have to have size for fill all space in EPROM ? if yes, what i can do that when my ROM is < 4MB ? eg: Zelda ROM have 1024 kb. I must merge 4 of copies the same file ?

2. i don't quite know what is difference between HIROM and EXHIROM?

Sorry for my English and thanks for Your answer

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Mon Jun 15, 2020 4:30 am
by poorstudenthobbyist
1 - no you don't need to fill it up. But it wouldn't hurt anything.
2 - ExHiRom is basically the same as HiROM with some extra logic to control two 4 MB ROMs. If your game is 4 MB or less then you don't need ExHiRom.

I'm far from a professor lol but I'm glad my site could help!

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Tue Jun 16, 2020 7:37 am
by kataklysm101
poorstudenthobbyist wrote:
Mon Jun 15, 2020 4:30 am
1 - no you don't need to fill it up. But it wouldn't hurt anything.
2 - ExHiRom is basically the same as HiROM with some extra logic to control two 4 MB ROMs. If your game is 4 MB or less then you don't need ExHiRom.

I'm far from a professor lol but I'm glad my site could help!
Thanks for Your reply :) i will try burn some roms :)

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Tue Jul 07, 2020 4:44 pm
by Kayumba
kataklysm101 wrote:
Sun Jun 14, 2020 3:03 pm
Hi, thanks for reply.
I was make board adapter nad use a donor cartridge, the adapter is from this site CLICK this is connection board for this Image

Im try to burn rom first time and i have willem programmer with adapter for 27C322. Can you tell me how to prepare rom in good way ?
another question is what kind of file i should burn ? *smc *sfc ? my rom oryginally is smc. Willem can programm it with 16 bit mode (word mode).
I was try to burn my file today but i have error at end of burning (0xFF)
Is it for HiRom or LoRom ?

Re: how to burn 8 mbit rom to 32 mbit eprom

Posted: Tue Jul 07, 2020 6:44 pm
by poorstudenthobbyist
Both. This table is from the perspective of the original ROM socket. So all the address numbers are the ROM address numbers.

i.e.
ROM A15 goes to CPU A15 on HiROM
ROM A15 goes to CPU BA0 on LoROM

But the A15 pin number is always the same. The connection to the cart connector is just different.