Interface with SD card

Discussion of developmental aspects of the MiSTer Project.
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jotego
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Interface with SD card

Unread post by jotego »

Hi,

I need to dump to the SD card the contents of a small EEPROM used in a core. Could you point me to information about how to interface with the firmware to save and read to a file? The core is an arcade so the name of the file could just be derived from the MRA, I suppose.

Thank you
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Coffea
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Re: Interface with SD card

Unread post by Coffea »

Can you post details of the actual EEPROM - A chip or whatever it is that has the data you need, picture & part number, I'm a little unclear on exactly what you're trying to accomplish.
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Re: Interface with SD card

Unread post by jca »

I suppose he wants to emulate an EEPROM in an arcade core and has to save it in a file on exit and reload it on starting the core so it does not really matter what the real EEPROM is.
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Re: Interface with SD card

Unread post by MJY71 »

Certain arcade platforms saved/recalled their 'DIP switch' settings to/from an EEPROM.
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jotego
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Re: Interface with SD card

Unread post by jotego »

It is an EEPROM found in arcade games, sized 128 or 256 bytes. I have it already talking with the core and modeled in a BRAM block.

I just need a way to get a serial stream of bits in from the SD card, when the core loads. And then get a stream out on the core request. The name of the file can just be linked to the game name in the MRA file.

There must already exist such an interface in MiSTer. I just need to know the details of it.
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Re: Interface with SD card

Unread post by retrorepair »

Would the computer cores not already do this with floppy disks?
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MottZilla
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Re: Interface with SD card

Unread post by MottZilla »

What about the console cores like SNES and Genesis? Wouldn't they be doing the same thing you need for games with SRAM?
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Re: Interface with SD card

Unread post by retrorepair »

MottZilla wrote: Thu Dec 10, 2020 7:37 am What about the console cores like SNES and Genesis? Wouldn't they be doing the same thing you need for games with SRAM?
Minus the "save when the core wants" but yeah pretty much exactly the same thing I'd have thought.
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Re: Interface with SD card

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