Eeprom And Flash Experiments Options

[SiliconIce]

Might interest some here

Some news on the XBH forums, posted by cjack (see the xboxhacker.net frontpage for news items):
XboxHacker.Net

-Two systems, Core with EEPROM, Premium w/o EEPROM...

And some of cjack's experiments:

Uff, just desoldered the tsop of my two x360 and inverted
Tsop of Premium soldered on Core console .... NO GO. Ring of light blinked red ... black screen.
Just resoldered the tsops in correct consoles....everything ok, consoles works fine. Just an experiment...more to come.....

And later:

Some other interesting findings:

1)Just desoldered the eeprom from my x360 core and......ehehehehhe....the console works fine without the eeprom too!!!!! Dashboard version and Kernel versions (backup version too) are the same of when there was the eeprom.... Everything works fine, games boots without problems....xbox live too......

2)I have swapped the dvd players just for fun and ..... the games won't boot....x360 tell you "To play this disc, put it in an xbox 360 console". So I think that x360 have some kind of segnature of his dvd player and won't boot games without it!

More exps to come

(if you come over to XBH, remember -- the "Technical" section of the boards are for serious technical discussion and work only, think before posting thanks! :-) )

[PCBUILDERCHRIS]

nah well stay true and here like we always did so go away recruiter sounds boring

why your saying keep it simple when some off the best things come from out of this world ideas responses and jokes

[cpuengineer]

That small flash chip near the cpu looks interesting. Almost looks like interface for JTAG EMULATION on all microprocessors...

This post has been edited by cpuengineer: Jan 8 2006, 09:08 AM

[cpuengineer]

After looking further at the board...

1. The 25020AN has a SDO and SDI. The JTAG interface demands TDI and TDO.
2. Also, why would MS interface a 20Mhz chip with a 3.2Ghz processor....
3. Some models have it but others dont due to lack of need for debug circuitry...
4. A 6 pin header test socket right next to the 25020AN chip.
6pins=TDI,TDO,TRST,TMS,TCK,and GND...

OMG. THIS HAS TO BE JTAG!!!

Picture of flash and socket:
http://www.free-hp.com/userdaten/38928917/...x360/eeprom.jpg

Check it out these engineering articles about JTAG...
http://www.inaccessnetworks.com/ian/projec...jtag-intro.html
http://www.us.design-reuse.com/news/news8974.html

This post has been edited by cpuengineer: Jan 8 2006, 09:35 AM

[bowser22]

This does look like a JTAG

[cracker666]

Dec. 08, 2005

IBM's DeveloperWorks website has published a paper on the Xbox 360 CPU. The paper offers an introductory yet technical look at the chip's design and development process, core architecture, frontside bus architecture, debugging interfaces, and more. It was given by Chief Engineer Jeff Brown at the Fall Processor Forum.

According to Brown, the Xbox 360 processor project involved demanding requirements for performance, cost, and production deadlines. Brown's team jumpstarted development by leveraging existing PowerPC and subsystem technology, he says.

The Xbox 360 chip uses three of the fastest-available (3.2 GHz) PowerPC cores, in a cache-coherent symmetrical multiprocessing architecture with a 1MB L2 cache and a frontside/physical bus speed of 5.4 GHz. In addition to supporting the full 64-bit PowerPC ISA (instruction set architecture), each core is specialized with "VMX128" extensions, similar to VMX instructions in G4 and G5 CPUs, Brown writes.

The chip offers a variety of debugging features, including JTAG, a POST monitor, and a serial EEPROM interface. It also uses extensive clock gating to save power.

Though labeled "introductory" by DeveloperWorks, Brown's article offers considerable technical detail about the Xbox 360's cores, debugging facilities, frontside bus architecture, and more. Read Brown's Xbox 360 whitepaper here.
http://www-128.ibm.com/developerworks/powe...nxw09XBoxDesign

[Wolves]

Please explain to me, what is JTAG used for?

[littlestevie360]

JTAGls are inline programmers, meaning that the device can be programmed and tested after the device has been assembled, they are very common in computer controlled equiptment

[vax11780]

Yes, I know I'm resurrecting an old thread....

Has anyone recorded the revision code of the processor for systems with and without the EEPROM?

I would guess the serial EEPROM stores microcode patches required for early versions of the processor that have bugs. Later versions (with the bugs fixed) don't need the EEPROM.

[lllsondowlll]

sorry for bumping*

Just desoldered the eeprom from my x360 core and......ehehehehhe....the console works fine without the eeprom too!!!!! Dashboard version and Kernel versions (backup version too) are the same of when there was the eeprom.... Everything works fine, games boots without problems....xbox live too......

Uh... stupid question but doesn't XBL bans require you to have an eeprom?

[Spark]

It did on the original console, that's what they used to ban modded units, maybe it doesn't with the 360 though.