Topic: Serial Kd (kernel Debugger) Question (Read 221 times)

pengj · « **on:** December 15, 2005, 10:44:00 PM »

I was browsing XDK document. It mentions that there is kernel debugger through serial port. Have any one use this before ?

By searching in this forum, it seems there is special little daughter PCB connect to LPC bus of Xbox Dev/Debug Kit. Does anyone have details information ? such as how does the PCB looks like ? Maybe we can create the PCB on our own ?

This post has been edited by pengj: Dec 16 2005, 06:47 AM

old engineer · « **Reply #1 on:** December 16, 2005, 10:17:00 AM »

Yep, you can use it to debug the Kernal whilst in retail mode.

...Unfortunately you don't seem to be able to post pics on this forum otherwise I would of posted a pic of the pcb in question.

pengj · « **Reply #2 on:** December 16, 2005, 04:13:00 PM »

old_engineer:

Can you describe more details on this PCB ?
Have you ever use serial kd ? I would assume you just connects PC's serial to the PCB with any terminal software.

QUOTE(old engineer @ Dec 16 2005, 09:24 AM)

Yep, you can use it to debug the Kernal whilst in retail mode.

...Unfortunately you don't seem to be able to post pics on this forum otherwise I would of posted a pic of the pcb in question.

Pikkon · « **Reply #3 on:** December 16, 2005, 07:52:00 PM »

Here is a old pic of mine.

(IMG:http://i4.photobucket.com/albums/y101/pikkonson/serialport.jpg)

Paintballpsyco2369 · « **Reply #4 on:** December 16, 2005, 08:21:00 PM »

I have also read parts of the XDK help file which mention Kernal Debugging, But I am wondering if the only purpose of the kd is for debugging. I am also wondering that if it offers any kinds of advantages over standard debugging procedures.

pengj · « **Reply #5 on:** December 17, 2005, 12:18:00 PM »

QUOTE(Pikkon @ Dec 16 2005, 06:59 PM)

Here is a old pic of mine.

IPB Image

Pikkon,

I think the PCB on the right is used for kd. I guess the header on the left connects to xbox mainboard's LPC.

The little IC under the SertialPort connector is RS-232 driver. As far as the TQFP one, though the picture is somewhat blurring, I suspect it's either FPGA or SuperIO. The last chip, the taller one next to TQFP, my guess would be voltage regulator IC.

Few more questions for you

1) I assume you only need terminal software(such as termTerm, SecureCRT, or Procomm) on the host , right ?
2) Also, I think the target(i.e. xbox) also need a stub running on it. And, the stub is probably part of the debug bios.

My thinking is you can convert normal xbox to debug enviroment by using XDKRecoveryDisk. Then, by hooking up the LPC PCB, you should get serial kd.

The beauty of serial kd is that you can debug xbox processes without any interruption(it's my guess, I never use it). The xbdm method over ethernet is great, but you lost connection when it launches another xbe.
For example, you attached to xbox in Evox Dashboard, then you lauched a game from Evox. After that, you lost connecttion to xbox, you needto re-attach agagin. Sometimes, my VS2003 even froze.

Serial kd should not have this problem. If xbox crashed before you had a chance to connect to it, you cannot attach to it.

Agent ME · « **Reply #6 on:** December 17, 2005, 12:41:00 PM »

No, an XDK Recovery disk will screw over anything other than a debug kit xbox.

Anyways, what exactly is kernel debugging?

pengj · « **Reply #7 on:** December 17, 2005, 01:44:00 PM »

As far as I know(by goolging), xbox debug kit is nothing but normal xbox with 128Mb ram + XDkRecoveryDisk installed. Some version of chips(such as NV) might be different, but it seems there is not difference in term of functionaly.

This is the info I know, I might be wrong though.

QUOTE(Agent ME @ Dec 17 2005, 11:48 AM)

No, an XDK Recovery disk will screw over anything other than a debug kit xbox.

Anyways, what exactly is kernel debugging?

pez2k · « **Reply #8 on:** December 17, 2005, 07:18:00 PM »

The XDK recovery disc will wipe the console's EEPROM and HDD, and attempt to flash a debug BIOS to the TSOP. Presumably a debug BIOS will boot without a valid EEPROM (else devkits wouldn't boot

), but no others will. Really, any pre-1.6 Xbox with a debug kernel TSOP flash, 128mb of RAM and the XDK dash installed is functionally a debug kit (while the dev kit has these extra two boards), but the important thing is of course to make sure you're booting a debug BIOS before ever even considering putting the XDK recovery disc in your Xbox. There was a thread in Newbie Chat just the other day by some lad who'd managed to wreck his retail Xbox with it because he had ignored the warnings.

pengj · « **Reply #9 on:** December 19, 2005, 03:18:00 PM »

I know that, thanks the warning though.
The debug bios I used currenly is not from MS, but IND-bios. It works great except it doesn't have debug symbol.

QUOTE(pez2k @ Dec 17 2005, 06:25 PM)

The XDK recovery disc will wipe the console's EEPROM and HDD, and attempt to flash a debug BIOS to the TSOP. Presumably a debug BIOS will boot without a valid EEPROM (else devkits wouldn't boot (IMG:style_emoticons/default/tongue.gif) ), but no others will. Really, any pre-1.6 Xbox with a debug kernel TSOP flash, 128mb of RAM and the XDK dash installed is functionally a debug kit (while the dev kit has these extra two boards), but the important thing is of course to make sure you're booting a debug BIOS before ever even considering putting the XDK recovery disc in your Xbox. There was a thread in Newbie Chat just the other day by some lad who'd managed to wreck his retail Xbox with it because he had ignored the warnings.

ffffff · « **Reply #10 on:** April 30, 2006, 01:50:00 AM »

QUOTE(Pikkon @ Dec 17 2005, 03:59 AM)

Here is a old pic of mine.

IPB Image

Hi,
If anyone have the serial board, could you please take a photo for the TQFP chip on it? It should be a Super IO chip and I think we can create this board if we have more details. Thanks in advance!

QQ_ghost · « **Reply #11 on:** November 25, 2009, 07:03:00 AM »

If someone were to reverse engineer the communication of an actual debug bios with the LPC port, I am sure that a LPC -> RS-232 shouldn't be too difficult... at least not for those with a bit of CPLD experience (which I lack). Find the speed, voltage and protocol of the target device to build. Then, post it to a forum such as this one and an engineer might pick it up... Hell, I might give it a go to hack one out.

obcd · « **Reply #12 on:** November 27, 2009, 02:17:00 PM »

Just the number on the TQFP chip would be very helpfull. I think it's a super io chip with an LPC interface. They were used on cheap PIII pc mobo's to add the legacy ports on the mobo. They usually contain 2 serial ports, a printer port and a floppy controller.

So, it wouldn't suprise me that the comport is simply on one of the legacy comport io adresses like the 3F8 or 2F8. I think the Io adresses need to be programmed in the chip. Once those are set (which is done by the bios in a pc) you can lock the adress programming register so that it becomes invisible.

A proper datasheet of that chip would be a great help. The other chip's are probably a level converter for the rs 232 port, and a xtal oscillator or a voltage regulator for the chip.

regards.

Author Topic: Serial Kd (kernel Debugger) Question (Read 221 times)