Continuing the comm port discussion...

Look in the back of the Saturn... the port is called Communications Connector, it's where the Saturn link cable goes.

About the serial interface, that's _very_ interesting. Maybe it was used for the Floppy drive that connected in this port. After I get this working, I can check if it's compatible or not.
Way, more of me poor monologue
. Anyway, I updated the page

With a new, fixed schematic and *gasp* a power LED

Also, as you might know I've been using BSch to make the schematics for this project. As people found the program interesting, I made an unofficial english version:

I'm translating the documentation as well, but not with great hurry.


Staff member
Don't feel like you're the only one interested... I just started a new job a couple weeks ago and have had a bit less free time for my various design rantings...

With a new, fixed schematic and *gasp* a power LED

Have you considered the possibility of making it a Saturn Tx LED? I'm guessing that a general activity LED would probably add too much complexity to be worth it, but it could serve as a quick and dirty diagnostic tool. However, I don't know if the SH-2 provides enough current to drive an LED directly...
Yeah, i considered TX/Rx LEDs as well... alas, Hitachi docs for the sh7604 claim maximum output current for the pins is 2.0mA, so i'd have to add a gate logic device to power the leds instead ^^; We'll see about that on the final design... Mutch like the MIDI port i'm considering
Oke, first the good news. I've finnaly put the schematic together , and I have a prototype ready for testing.

Bad news:

1) The +5V from the Saturn seem to be there only for show. Connecting the MAX232, a minimal consuption device, drops the voltage to around 2V. The current schematic has to feed from the printer/joystick port...

2) I'm having trouble mapping all the pins to the inhards of the cable, I'll be using one of my disassembled saturns to check that problem tomorrow.

3) The biggest one : my code doesn't work >_<;. Saturn is refusing to send any data so far... Could someone tell me at what clock speed speed a PAL (50Hz) Saturn runs?
Part 1 of the project - Build a cable that uses the serial port on the back of the saturn, allowing us to link the saturn to the PC. This is aproaching completion. I can't seem to find the 5V pin, altough. I have to completely destroy one of the plugs to find out were it's placed.

Part 2 of the project - Develop a set of libraries that alows one to send and recieve data from the Saturn. Develop a program that allows one to upload code, mutch in the same way one would use a PAR to do so.

Part 3 of the project - Due to the fact that getting the Link cable that was used in Part1 might become hard (thank you Akuma, btw ^o^), develop a version that can be soldered inside the machine.



Mid Boss
hey that's GREAT!
:agree w00t! but... are you guys gonna sell one? i don't really want to solder anything on my saturn.
so are you guys succesfull? what if there is speed problems? or are you guys still going to use SSFEXE.EXE to transfer files ... ? oh BTW, this is extremely off-topic and i'm sorry for this but i don't really want to create another annoying Topic. How would i set True Transparency? you know like in Albert Odyssey where the Big Dragon is floating and he has a shadow... and the clouds go by a house ... how is it done? i seen a function in 237.pdf slShadow(); i don't think that's it...
thanks. good luck with this project and don't quit!
The solder version is the version you can built with easily avaiable parts, but the version based on a link cable should require no solder. The uploader is provably gonna be a separate program, and it's provably gonna be slower than a PAR. I'm going for a cheap alternative, not a faster one.

As for the transparency, it's too hot around here to awnser


Mid Boss
cool!, hey if you get this to work... will you sell me one for MEGA cheap? im the cheapest bastard on SX! hahaha smile.gif oh too hot for transparency? get yourself a fan then we'll talk cool.gif laugh.gif biggrin.gif cheers.gif oh hey BTW, what is the #define for NBG0 and NBG3 ? can you guys please tell me? thanks.


Staff member
Nescphp, I can only give you that, i don't know if it's enough for you :

#define NBG1_CEL_ADR ( VDP2_VRAM_A1 + 0x02000 )

#define NBG2_CEL_ADR ( VDP2_VRAM_A0 + 0x02000 )

#define NBG3_CEL_ADR ( VDP2_VRAM_B0 + 0x00000 )

#define NBG1_MAP_ADR ( VDP2_VRAM_B1 + 0x12000 )

#define NBG2_MAP_ADR ( VDP2_VRAM_B1 + 0x14000 )

#define NBG3_MAP_ADR ( VDP2_VRAM_B1 + 0x16000 )

#define NBG1_COL_ADR ( VDP2_COLRAM + 0x00200 )

#define NBG2_COL_ADR ( VDP2_COLRAM + 0x00400 )

#define NBG3_COL_ADR ( VDP2_COLRAM + 0x00600 )


#define RBG0_CEL_ADR	(VDP2_VRAM_A0	)

#define RBG0_MAP_ADR	(VDP2_VRAM_B0	)


#define RBG0_KTB_ADR	(VDP2_VRAM_A1	)


#define BACK_COL_ADR ( VDP2_VRAM_A1 + 0x1fffe )
Originally posted by nescphp@Jun 19, 2003 @ 10:27 PM

what is the #define for NBG0 and NBG3 ?

vbt already gave you a couple of #define values for the cell format of NBGs, but I'd like to add that you can put the vram for NBG3 anywhere you want, you will only need to tell your Saturn about it. I think you already know the SGL functions to do so. Please don't forget to put your data where you told your Saturn it'd be.
Originally posted by Reinhart@Jul 21, 2003 @ 10:55 AM

How goes this interesting project ?

In more trouble than I originally belived this would be - My software is still unable to send data from/to the PC. This might be due to incorrect information on the Communications Connector, or due to improper initialization of the software to the SCI port(what seems unlikely). Meanwhile, it seems like my ISO creating technique (using mkisofs) doesn't like Saturn very mutch - I've been using the single swap technique, because the IP.BIN on my burn is being refused... So, not much progress yet.


Staff member
Meanwhile, it seems like my ISO creating technique (using mkisofs) doesn't like Saturn very mutch

How are you going about making an image with mkisofs? You might want to have a look at the SMS Plus build files here; I'm pretty sure that I produced a working image with it, though it was a while ago...
Bah, i've been generating it with

mkisofs -G IP.BIN <directory> > filename.iso

That, now considering your command line, it's hardly correct ^^;