D0 point and their meaning

[ChriZz]

Hello, I have one or two questions regarding the D0 point.

With an xbox with version 1.6 the whole thing is called lframe (what does this abbreviation mean?) and it has been confirmed by various people that there are several mAh tiles and if you simply short-circuit this line with ground "could" damage the mcpx chip. Therefore the lframe cut is recommended. So far everything is known and at least for 1.6 I do it that way.

Now to my question. What about D0 ... what does D0 even mean and where does it come from, also from mcpx? Tiles there also several mAh? I don't know about you, but I always have a bit of a stomach ache when a conductor track is to be short-circuited for which it was not actually intended.

Hope you understand my english. Greetings

[KaosEngineer]

D0 grounded is an intended operation to control where the MCPX loads the BIOS on startup.  D0 grounded (0) [Parallel Data bus bit 0 = 0] load the BIOS from an LPC connected flash memory chip.  D0 [Parallel Data bus bit 0 = 1] load the BIOS from the parallel attached flash memory chip on the motherboard.

The first byte of the BIOS has the value 09. If you don't force the D0 data bus line to ground, the D0 bit is HIGH.  Thus, telling the MCPX to load the BIOS from the TSOP parallel attached flash memory chip on the motherboard.

Quote

 

DDDDDDD
76543210
-----------
00001001

 

Edit:  Based on that info - D0 controls where the MPCX loads the BIOS from: TSOP parallel attached flash memory chip (D0 = 1) or LPC attach flash memory chip (D0 = 0).  I wonder if D3 also controls some operation of the MCPX on startup.

[ChriZz]

Thank you Kaos