N64 rom adapter

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Frankym2612
Posts: 36
Joined: Thu Jun 27, 2019 8:25 pm

N64 rom adapter

Post by Frankym2612 » Thu Feb 25, 2021 9:05 am

Hi all I have made various rom adapters for Nes Snes master system genesis and now I want to try N64 but from what I read it’s not so straightforward and I admit I don’t know how the N64 roms work and can’t find any info online is it possible and can I get some help?

lidnariq
Posts: 10435
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: N64 rom adapter

Post by lidnariq » Thu Feb 25, 2021 1:15 pm

N64 has a multiplexed address and data bus, so you need extra hardware to convert that into something that could be used with a conventional NOR flash ROM.

To wit:
With ALE_H high, everything is disabled
On a falling edge of ALE_H, AD0-AD15 should be latched and become A16-A31
On a falling edge of ALE_L, AD0-AD15 should be latched and become A0-A15
On a rising edge of /RD or /WR, the address should be incremented to the next 16-bit word; for at least 256 words. (This is configurable by the ROM header, but no less than 2 words and no more than 65536)

Carts that have any save memory at all require even more hardware.

Frankym2612
Posts: 36
Joined: Thu Jun 27, 2019 8:25 pm

Re: N64 rom adapter

Post by Frankym2612 » Thu Feb 25, 2021 3:02 pm

Thank you!

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