32Mbit Multirom 2in1 diagram

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Kayumba
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32Mbit Multirom 2in1 diagram

Post by Kayumba » Tue Feb 02, 2021 12:36 pm

Hello,

Can somebody share schematic diagram for 32Mbit Multirom EPROM 2in1 ?
I tried to use 74HC74 flip-flop chip for 2 games x 16Mbit with this diagram but it doesn't work. :cry:
I use method of combine two files with command line "copy /b"
Thank for help.
Image

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poorstudenthobbyist
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Re: 32Mbit Multirom 2in1 diagram

Post by poorstudenthobbyist » Tue Feb 02, 2021 3:00 pm

Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

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Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Tue Feb 02, 2021 4:45 pm


Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Wed Feb 03, 2021 7:14 am

So, if i get right...
- For 2X16mbit on one 322 eprom: use adress pin A21
- For 4X8mbit on one 322 eprom: use adress pin A21 and A20

Is that right?

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poorstudenthobbyist
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Re: 32Mbit Multirom 2in1 diagram

Post by poorstudenthobbyist » Wed Feb 03, 2021 8:49 am

Technically A20 and A19, since it's a 16-bit databus, but yep the highest address pins.
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

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Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Wed Feb 03, 2021 4:07 pm

poorstudenthobbyist wrote:
Wed Feb 03, 2021 8:49 am
Technically A20 and A19, since it's a 16-bit databus, but yep the highest address pins.
Why technically ?

lidnariq
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Re: 32Mbit Multirom 2in1 diagram

Post by lidnariq » Wed Feb 03, 2021 4:13 pm

The datasheet for the 27C322 calls those pins A19 and A20.

But in a machine using a 68000, those same pins are connected to 68k A20 and A21.

Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Wed Feb 03, 2021 7:18 pm

lidnariq wrote:
Wed Feb 03, 2021 4:13 pm
The datasheet for the 27C322 calls those pins A19 and A20.

But in a machine using a 68000, those same pins are connected to 68k A20 and A21.
I tried to do for 4in1 (4x8Mbit) like that, but it's doesn't work ...
Why? Is there something wrong?

For LoROM :
A21=> pin 42 (27C322)
A20=> pin 1 (27C322)

Image

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Re: 32Mbit Multirom 2in1 diagram

Post by lidnariq » Wed Feb 03, 2021 7:38 pm

crop_38ce5c6eae8cf7c71d7ed38bd2f56285.jpg
crop_38ce5c6eae8cf7c71d7ed38bd2f56285.jpg (14.85 KiB) Viewed 2219 times
Uh. You might to look more closely at what you wrote.

Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Thu Feb 04, 2021 6:01 am

lidnariq wrote:
Wed Feb 03, 2021 7:38 pm
crop_38ce5c6eae8cf7c71d7ed38bd2f56285.jpg
Uh. You might to look more closely at what you wrote.
Thats why it not working :lol:

Here is corrected visual schematic for 27C322 LoROM / HiROM with 74HC74 flip-flop chip:
Image

How about SAVES ?
Will it works to save game progress ?
If for example, I have one file with 2 games that each of ONE need SRAM 6264 (8kB), can I keep ONE SRAM 6264 for two games?
Or better to put bigger SRAM, like 62256 ?

Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Tue Feb 09, 2021 5:42 pm

I I will use 2in1 multirom,
How to do if both 2 games will using 64K SRAM CHIP ?
Will it work with one ?

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poorstudenthobbyist
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Re: 32Mbit Multirom 2in1 diagram

Post by poorstudenthobbyist » Tue Feb 09, 2021 5:49 pm

Apply the same method in the multicart article to the SRAM. It holds data in the same way as a ROM does (it just gets erased if power is removed).
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

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Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Tue Feb 09, 2021 5:58 pm

poorstudenthobbyist wrote:
Tue Feb 09, 2021 5:49 pm
Apply the same method in the multicart article to the SRAM. It holds data in the same way as a ROM does (it just gets erased if power is removed).
Ok,
but Will it be good enough one SRAM 64 for two games that each one need 64 ?

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poorstudenthobbyist
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Re: 32Mbit Multirom 2in1 diagram

Post by poorstudenthobbyist » Tue Feb 09, 2021 6:14 pm

Can you put two 32Mbit ROMs on one 27C322?
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

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Kayumba
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Re: 32Mbit Multirom 2in1 diagram

Post by Kayumba » Tue Feb 09, 2021 6:19 pm

poorstudenthobbyist wrote:
Tue Feb 09, 2021 6:14 pm
Can you put two 32Mbit ROMs on one 27C322?
No.
I talking about 2 games x 16Mbit = 32 Mbit (27C322 Multirom)

But each 16Mbit game need 6264 SRAM.
If on my board I will keep one 6264 SRAM, I dont know how each game will save data, will it be good enough space for each one?

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