USB Downloading Device for Sega Saturn

gameofyou1

gameofyou1

Hello,

After a recent Action Replay Cartridge failure (in which I lost every game-save I ever had), I decided to design and build a USB based device which would allow me to upload/download gave-saves to the Saturn. I am a couple months away from completion of this DataLink device. When I am finished with the testing phase, I will offer to build these for anyone interested. I tried to make this device as inexpensive as possible, but the price will probably be around $50. The USB components especially are expensive in such small quantities. Anyway, I have put up a preliminary website for the Saturn USB DataLink device:

http://members.aol.com/gameofyou1/SaturnPAR.html

I will post again when my testing is completed.
 
Woohooo!

OK, I finished coding and testing for the game-save transfer functions & it all works! I can get the game-saves from the Saturn over the USB link and save them to the harddrive. Then I can erase the Saturn memory, and transfer the game-saves back by using the harddrive file.

Now I just have to add the software for downloading homebrew games...
 
gameofyou1 said:
Hello,

After a recent Action Replay Cartridge failure (in which I lost every game-save I ever had), I decided to design and build a USB based device which would allow me to upload/download gave-saves to the Saturn. I am a couple months away from completion of this DataLink device. When I am finished with the testing phase, I will offer to build these for anyone interested. I tried to make this device as inexpensive as possible, but the price will probably be around $50. The USB components especially are expensive in such small quantities. Anyway, I have put up a preliminary website for the Saturn USB DataLink device:

http://members.aol.com/gameofyou1/SaturnPAR.html

I will post again when my testing is completed.
Click to expand...

OK, I have now completed the software and testing for downloading Homebrew games to the Saturn. I can now make these for whoever wants one. Just send me an email (there's a link on the webpage).
 
The speeds reported on your webpage are rather poor. You're not actually exchanging one byte at a time over USB, are you?
 
just wanted to leave a msg and say i'm definitely interested. i've got an 3 saturns (2 mk-80000 and 1 mk-80000a) but no mk-80001 with a 1.01 bios although i'm on the hunt for one. as soon as i can find a 1.01 bios us saturn i'll definitely be ordering one :)
 
antime said:
The speeds reported on your webpage are rather poor. You're not actually exchanging one byte at a time over USB, are you?
Click to expand...

The speed could definately be improved by making a more expensive design. My goal for this project was to create a device at the lowest cost possible. And initially, I had only planned to transfer game-saves, which are quite small (64K). I transfer packets of data (limited by my uP's ram) over the USB.
 
You should be able to get much higher speeds even with the parts you're using. Larger transfers are good for efficiency, and can easily be achieved with some protocol awareness in the microcontroller. Also check your transfer sizes - the FTDI chips will send two status bytes in each 64-byte USB packet and if you don't take them into account it can drop your speeds to a fraction of what you should be getting (there's an app note on this).

BTW, are you using a FreeWing implementation or the "full" Commlink?
 
antime said:
You should be able to get much higher speeds even with the parts you're using. Larger transfers are good for efficiency, and can easily be achieved with some protocol awareness in the microcontroller. Also check your transfer sizes - the FTDI chips will send two status bytes in each 64-byte USB packet and if you don't take them into account it can drop your speeds to a fraction of what you should be getting (there's an app note on this).

BTW, are you using a FreeWing implementation or the "full" Commlink?
Click to expand...

Yes this is true. I am not ruling out the fact that the current design can be further optimized. I was so happy just to get the device working, that I really haven't put much thought into optimizing the speed yet :)

I will look into your suggestions for speed increase. Thanks for the feedback.

As far as the Freewing question, I'm afraid I really don't have any idea what you're talking about. I made the design based on the documents posted here at SegaXtreme. Feel free to send me an email if you want to talk specifics about the design/firmware.
 
gameofyou1 said:
DOH! I just fixed a bug in my Windows application software, and it increased the speed by a factor of 2.
Click to expand...

That is good news. Especially for testing homebrew, it's crucial to have short uploading times.

Also importand: is your PC client portable? It would be cool to have a Saturn linkup to a MacOS X machine...

Before making a final release, I recommend some more attention to transfer rates. Then, I'm really interested to buy such a thing! The picture on your website looks very nice and professional! Thanks for your work!
 
OK, I am only a few days away from locking down the hardware/firmware design. I have an extremely nice fellow from Texas helping me with the testing. Just as an aside, we have discovered that the game-save files are directly compatible with the emulators SSF and Cassini.

I have done what I can in hardware to speed up the process (faster USB bit-rate, hardware handshaking, ...etc.). I think that the result will still disappoint Antime & Rockin B. It won't be anywhere near 100Kbytes per second. Of course, the software could be scrapped and begun from scratch to make some speed improvements (probably), but I don't see that happening anytime soon. I will update my web page with the correct transfer speeds when I have completed testing.

Anyway, after the hardware/firmware are locked down, the remainder of the updates (dumping the bios, ...etc.) will just be windows software updates that can be emailed (or maybe even hosted on my site). So I will open up orders after the hardware/firmware is finalized. Please email me if you would like one made for you. It takes a lot of assembly time to put one together, and I may not always have all the parts I need. If you email me, I will be able to tell you how long it will take to build.

I am taking a lot of flak on other boards over the price. I am making very little money from these. At $50, it's almost not even worth my time to do it. When I use up my rev1.0 boards (which require mods), I think what I might do is offer to sell just the Software, bare pcb, programmed cpu, and parts list. Then if people think they can build it cheaper, they can have at it. I have plenty of other things I could be doing with my spare time (like playing games :) ).
 
Is it possible to re-program the microcontroller over USB, via the bit-bang modes? I see that the pins required are connected to somewhere.
 
antime said:
Is it possible to re-program the microcontroller over USB, via the bit-bang modes? I see that the pins required are connected to somewhere.
Click to expand...

I'm not sure about that, antime. The data sheets at Atmel will be able to tell you if the device is programmable from the uart. However, there is a 10 pin header on the board which allows for reprogramming the cpu's flash(that's the way I do it). So if you were thinking about loading your own software into the cpu, yes, it would be very easy for you.
 
I was really asking if the MOSI/MISO pins were already connected to the FTDI module, but I suppose not (that would be an interesting/useful change for eventual future revisions of the board). Programming over the UART is unfortunately not supported.
 
I got my unit in the mail yesterday. Works like a charm..

I00858.jpg
I00859.jpg
 
scott21 said:
whats new in the 1.02 software update btw? any changelog?
Click to expand...

I will try to get a changelog added to the webpage. V1.02 is just the software required for use with the "higher speed" final hardware configuration. I had a couple units out for testing with the previous hardware configuration, which had used v1.00 & v1.01 of the PC software.

I have been too busy building hardware to do any "real" software updates. The next thing I am going to add is the bios dumping feature, though.

I will post a DataLink device on eBay every once in a while, because some people prefer to complete transactions that way.
 
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