Sega-Naomi

Hello, sorry for my english.



In any optical unit, the laser detect only 1 logic state every time, 0 or 1. Only 1 bit. This is the most basic data transmision. After, a digital circuit generate bytes and all complete information.



If in this moment, in the Beginning, When we have only a basic bit "torrent" conect the circuit to a pc For example usb, can send a simulated bit "torrent" similar to the optical unit.



Is this possible?



Is posible conecte the laser of a gd-rom to a pc With this theory and emulate a gd-rom disc?



Thank you for your time, Ponder it.

To emulate the optics would be needlessly complicated and unnecesary.



The best course of action would be to emulate it at the ATA layer. At this stage all you would need to do is to be able to duplicate the ATA command structure and match the DMA transfer speed.

Ok.

Your theory is really the best but you are having a lot of troubles decoding the sega packet inteface I'm looking for an alternative.



I'm have been thinking about decoding it recording an audio Cd with a few information in a critical time and then look for it in a logic analyzer.



Thank you for your time, Ponder it.

Who told you i was having trouble with the SPI ?



One would imagine without the confidential Sega SPI documentation it would be a bit of a problem. If you have any real technical questions then feel free to ask.

MrSporty wrote:Who told you I was having trouble with the SPI ?

inacete wrote:
Your theory is really the best but you are having a lot of troubles decoding the sega packet inteface I'm looking for an alternative.

i think inacete said you are having trouble with the spi.

ok continue with the question at hand.

GD-ROM Protocol SPI (Sega Packet Interface) Specifications Ver 1.30 12 January 1999



Table 3.3 ATA Commands



Soft Reset - 08h

Execute Device Diagnostic - 90h

NOP - 00h

Packet Command - A0h

etc etc ......



Table 6.1 Packet Commands



TEST_UNIT - Verify access rediness - 00h

REQ_STAT - Get CD status - 10h

REQ_MODE - Get various settings - 11h

etc etc .....



inacete is ill informed if he thinks i have problems with the SPI.



If you want to emulate the GDROM, doing it at the ATA level IS the most logical way. The only problem is that for most people its easy to say what they would like to do, yet not many of them follow it up with any real work or examples.



Eagerly pondering ..



MrS

Hello, sorry for my english, I am spanish.



Sorry for disappear, i was working



I believe that you have got angry with me.



I never wanted it.



I can create a workgroup of pople to implement gd-rom port (in dreamcast g1 port) to ide (hdd, usb, pen drive). If you are interestin in it, "I NEED YOU".



Thank you for your time, Ponder it.

this is the time you need a native english speaker with a good grasp of spanish.

if i understand what your upto,

you want to store gdroms and serve them from a pc,



dont waste time messing with ATA,

just put a decent-ish scsi card in the pc & hook it to the drive or naomi,



or fit 2 cards and do a "man-in-the-middle" trick.



scsi has no hardware difference between master & slave devices so it's easy.



then you just need to write the software.

Linux is gonna be your friend there because you can mess with the scsi kernel driver to get raw packets in & out, or even make a kernel driver that does bi-directional forwarding between 2 Lun's so you can make a simple packet sniffer while the naomi does it's thing.

mrsporty, or someone else Do you know at which layers the SPI operates? I've hooked up my GD to a SCSI controller, and it at least identifies itself.



http://www.t10.org/scsi-3.htm



I guess the device is parallel (narrow?) SCSI-2 at 10mhz.



Somewhat related:

http://micha.freeshell.org/ramdisk/index.php



Also, I believe complete SPI is in place in linux.