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Welshworrier

Something I've been working on

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While some people may think I just hang around the Atari section because I have a masochistic streak, I do actually have some interest in developing stuff for the jaguar.

 

It's to this end I thought I'd share a little video of something I've been playing with.

 

Disclaimers: it's still being developed, there's no price on it yet (but should be quite cheap), it works as is, tested upto 32gb at moment. It's part of another project I'm running with, skunkboard related, and sort of happened by accident. It's not a competitor for Saints much neater project.

 

And yes I'm rubbish at playing games one handed while holding a camera.

 

So without further ado:

 

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Further info: supports both read and write of files on fat32 formatted card, currently using 68k to access - DSP code soon, connects via the standard eeprom pins (almost all software to do the jiggery pokery) - meaning could fit a standard cart. Runs pretty much all homebrew code I've thrown at it - as you can see in the video.

Edited by Welshworrier
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Nice! Looks like it could be a cheap way to test code on the Jag. I take it this requires a boot rom replacement (currently at least)?

Edited by SainT

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I envisage it as a "fake" cartridge that has it attached. The cartridge ROM then boots the menu from the attached SD card but also has SD access routines built in. That way homebrew software could, in theory, read and write files from the SD card as required with a small ram overhead.

 

So no Jag boot rom replacement, just a small eprom board/programmed cart - I've currently interfaced it with a skunkboard for development.

Edited by Welshworrier
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If you release it, please discuss with SainT -- it would be nice for homebrew developers to have a single API for SD access that works on both hardware :)

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If you release it, please discuss with SainT -- it would be nice for homebrew developers to have a single API for SD access that works on both hardware :)

Will do - im using fat FS as the fat access code which just requires a few interface functions to be defined. As long as both access paths are specified (for both types of card) and a way of checking/setting type automagically then it would be transparent to the developer.

More info on fatfs here: http://elm-chan.org/fsw/ff/00index_e.html

Simplest way of doing that would be in the initialise function call - check for saint card and if fail use simple one instead.

Edited by Welshworrier
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Hello!

 

Will do - im using fat FS as the fat access code which just requires a few interface functions to be defined. As long as both access paths are specified (for both types of card) and a way of checking/setting type automagically then it would be transparent to the developer.

More info on fatfs here: http://elm-chan.org/fsw/ff/00index_e.html

A good choice, i am using this lib for my own SD-card project also.

 

Kind regards

Matthias

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Totally agree, there were a few gotchas along the way (scope was my biggest bugbear) but when I saw the data appear on the logic analyser the first time it gave me a big smile :)

 

I have visited your web site numerous times and must thank you for the great information on there.

post-44480-0-56141000-1509404490_thumb.jpg

Edited by Welshworrier
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That way homebrew software could, in theory, read and write files from the SD card as required with a small ram overhead.

 

 

 

Will you be taking pre-orders for these? If so, what is the maximum number somebody can order? I would love to work with this.

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Been rather busy in real life however:

1. Got some jaguar parts off eBay to build a cart. They arrived yesterday and were in a much worse condition than described - legs of the sockets they had put in were more like cankles and the eproms had soldered on legs in a few places. The pictures do not give the full horror of how bad they were. A nice person reworked the boards but I'm having to wait for a few eproms.

2. Got hold of programmer and eraser for chips.

3. Started on DSP conversion of access code to increase speed.

4. Got schematic correct now but needed physical board to size, trying to work out placement is issue - people would still need/want to access the SD card. Also wanted to confirm design inside shell.

 

It's progressing, just not at the rate I would like at the moment.

post-44480-0-79168000-1510699248_thumb.jpg

post-44480-0-34340900-1510699267_thumb.jpg

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Wow, that's horrific looking. Surprsied you could manage to do anything that stuff. Progress is progress though! Thanks for sharing, best of luck =D

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FWIW I've always had great success ordering EPROMs from China/HK on EBay, always clean pulls. Of course if time is a factor this info doesn't help.

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I ordered some 27c322s yesterday and should be delivered inside 3 days as UK based. They are pin compatible (except for the byte leg/a20 of course). They worked out at about a dollar each.

 

I also had to order a parallel port as the programmer is an old lv48.

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If they came from the same eBay seller I use, they come from Spain. Still only a few days for postage compared to 30+ for China.

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I've just messaged you with bit of background info but it's slowly progressing.

 

Bit of a breakthrough re: circuit board recently and hope to get some test boards made up soonish.

Edited by Welshworrier
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