Bios and Flash Ram

[Newbie]

Hi all,

I have a question about BIOS and Flash Ram of Dreamcast.

I want to try to read a part of the bios of my machine and Flash Ram.

I do not want to make something wrong, so carefully, i ask how it could it be done secure

First where can i start reading and how (some example source code would help) ?

Secondly, i wonder myself how many different BIOS exist from Dreamcast hardware.

I know there are US/JP/EU : but is there only 3 different versions ? more than that ? (I want to exclude from discussion the hardware devkits : for me it is not a standard console)

Finally, what the Flash Ram is useful for (i talk about programming interest).

Thanks.

[bogglez]

I haven't messed around with those myself, but according to http://dcemulation.org/?title=Dreamcast_Memory_Map they are mapped into the general memory address space. You can probably set a pointer to their address and read their contents like that.
The only interesting thing I can think of right now would be using the BIOS font for text display instead of providing your own font file.

[|darc|]

The Dreamcast does not use a different BIOS for different regions. The BIOS itself is universal, but the console reads the region information from a read-only section of the flash RAM and acts accordingly.

There are 3 known releases of the BIOS for the retail version of the console-- 1.004, 1.01, and 1.022. 1.022 has the support for booting CD-Rs removed and is pretty rare.

[Newbie]

Something like that could be correct ?

Code: Select all

uint8 * biosData = 0xa0000000; 

int index;

for(index = 0; index < 2097152; index++)
{
	printf("%c",biosData[index]); 
}

[Newbie]

The Dreamcast does not use a different BIOS for different regions. The BIOS itself is universal, but the console reads the region information from a read-only section of the flash RAM and acts accordingly.

There are 3 known releases of the BIOS for the retail version of the console-- 1.004, 1.01, and 1.022. 1.022 has the support for booting CD-Rs removed and is pretty rare.

In fact, there are 1.004(JP), 1.01c(EU/US/JP), 1.01d(EU/US/JP),1.022(EU/US/JP).

But i ask myself about v1.01a and v1.01b and perhaps other BIOS revisions ...