Interesting site with FPGA source code

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weirdocollector
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Interesting site with FPGA source code

Postby weirdocollector » Wed May 27, 2015 4:05 pm

Hi everybody,

I'm new to this forum: hope to find you all well !

Unfortunately (I'm studying but my free time is scarce), I'm not able to help in developing new cores, but I've stumbled upon a site that may be of interest for developers:

http://darfpga.blogspot.fr/

The author has recetly published on Sourceforge his C64 core with 1541 on SD card support, and the sources for the Bagman and Crazy Kong arcades are present: http://sourceforge.net/projects/darfpga/files/Software%20VHDL/

Hope this is of any help.

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vebxenon
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Re: Interesting site with FPGA source code

Postby vebxenon » Wed May 27, 2015 7:33 pm

Good :)
Just a computer and videogame lover :)

- Atari Jr 2600 clone
- Atari 7800 Peritel
- Atari XEGS
- Atari Lynx II
- Atari Jaguar
- MiST Board

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Gryzor
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Re: Interesting site with FPGA source code

Postby Gryzor » Fri May 29, 2015 5:56 am

Let's see who can port these... :)
Reality is that, which, when you stop believing in it, doesn't go away. --P.K.Dick

.:.
http://gryzor.info

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Newsdee
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Re: Interesting site with FPGA source code

Postby Newsdee » Fri May 29, 2015 7:40 am

I guess they need work to use the MiST SDRAM (instead if SRAM), support a FAT32 SD card to get ROMs /disks, and the USB keyboard. On top of remapping pins of the FPGA, if needed.

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MasterOfGizmo
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Postby MasterOfGizmo » Fri May 29, 2015 9:51 pm

I once was in contact with him. I think I even got the fpga64 code I have been using from him. The SD card floppy sounds interesting ...

But focus is currently on the Amiga ...

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Re: Interesting site with FPGA source code

Postby MasterOfGizmo » Fri Jul 10, 2015 1:05 pm

I've taken a closer look at this. Replacing the sram with the sdram actually wasn't too tricky. Adding OSD and keyboard also went fine and both the c64 and the 1541 seem to run as i can e.g. read the floppies error channel.

The tricky part is the sd card access. First, the 1541 wants to read 256 byte sectors which is unlike the typical 512 bytes per sector. The MiST currently doesn't support anything other than 512 bytes per sector. Actually many sd cards (especially the sdhc cards) also don't support anything other than 512 bytes per sector, so the original approach wouldn't work with many cards, anyway.

But the biggest issue is that this 1541 implementation doesn't read d64 files from a PC (fat) formatted sd card. Instead it expects the d64 images to be stored on the raw card. You'd need special tools to create such a card and a PC couldn't easily read and write this. Plus the MiST needs a proper PC/fat format to load the core file etc.

So this needs some major changes for an acceptable user experience ... but it can be done :-) One solution would e.g. be to store an entire d64 image in sdram and let the 1541 read it from there instead of letting the 1541 access the sd card itself in this rather brute force manner.
MIST board, FPGA based Atari STE and more: https://github.com/mist-devel/mist-board/wiki

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Newsdee
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Re: Interesting site with FPGA source code

Postby Newsdee » Fri Jul 10, 2015 2:13 pm

That's very encouraging news! Aside from the disk, how does it compare to the existing core? Is it a newer version of the source code it was based on?

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remowilliams
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Re: Interesting site with FPGA source code

Postby remowilliams » Fri Jul 10, 2015 3:44 pm

Ah, an expanded C64 experience would be great. :)

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MasterOfGizmo
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Postby MasterOfGizmo » Fri Jul 10, 2015 3:51 pm

The c64 itself is the same.

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Postby MasterOfGizmo » Sat Jul 25, 2015 6:22 am

This c64 with SD card is the base of the latest c64 core for the mist.


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