xbox360 chatpad, awsome backlit mini keyboard - Page 8

turbocad6 · 11-08-2007, 03:44 PM

yeah man, I could make my car fly before I could figure that out

inh · 11-08-2007, 03:49 PM

I get it. Hell I'd give it a shot if i had the time/resources.

My solution? Figure out how the keypad talks to the PIC, then desolder and replace with our own programmed PIC

greatwhite · 11-08-2007, 04:03 PM

Quote: Originally Posted by turbocad6

yeah man, I could make my car fly before I could figure that out

I dunno, looks pretty easy to get a car to fly:

Click here to watch the video

Close Move

LOL.

sporty_drew · 11-08-2007, 04:04 PM

Quote: Originally Posted by greatwhite

I dunno, looks pretty easy to get a car to fly:

Click here to watch the video

Close Move

LOL.

They fly for awhile, my problem is they always come back down

thermoptic · 11-09-2007, 12:16 AM

Quote: Originally Posted by inh

I get it. Hell I'd give it a shot if i had the time/resources.

My solution? Figure out how the keypad talks to the PIC, then desolder and replace with our own programmed PIC

Does PIC offer direct USB interface in their microcontroller product line? I haven't played with PICs in a long time. The Atmel AVR looks very USB friendly with complete HID driver compliant code. HID Keys is a 17-key USB keypad controller example for the AVR-USB:

HID Keys
http://www.obdev.at/products/avrusb/hidkeys.html

My thought is to cut out the keypad matrix decode logic and replace with the UART keypress data, which we read from the chatpad PIC. The chatpad PIC firmware already does the hard work of monitoring the keypad matrix to create the character. You press 'a', the PIC 16F883 decodes the keypad matrix and sends ASCII letter 'a' (0x61 hexadecimal) on the TX UART line. With one start bit, eight data bits, one stop bit, and no parity (known as 8-N-1) the 'a' would be sent out to the XBOX 360 controller on the TxD line as follows:

START BIT + EIGHT DATA BITS + STOP BIT
1 + 0 1 1 0 0 0 0 1 + 0

The AVR code decodes the 'a' character on its RxD UART line, sends the 'a' through the USB link to the HID USB device driver, and the OS drops an 'a' character into the active application. Piece of cake, right?

This assumes the PIC 16F883 sends simple ASCII characters for key presses. The protocol could be more complex. My approach also assumes the HID Keys example runs on the AT90USBKEY with little porting effort. The biggest part of this project is simply allowing the two pieces to communicate. It should be easy, but I am assuming many things.

UART Transfer
http://en.wikipedia.org/wiki/UART#Se...llel_Algorithm

ASCII Table
http://www.asciitable.com/

Google Bot has already found this thread (so many keywords). Excellent!

Let's hope somebody picks up this project.

inh · 11-09-2007, 05:00 AM

PIC has USB devices, but I doubt they would fit the same pinout.. I would just make it spit out a serial datastream of characters, or hell, PS/2 compatible stream, and just plug it in to the computer =]

Snortonnorton · 11-09-2007, 01:21 PM

hell, with minds like these I'm sure we could get this done. maybe someone could sell a usb linking adapter for it to pc on his forum.

turbocad6 · 11-09-2007, 01:58 PM

someone say the word & i'll send them a chatbox... anything else I could do to help to I would, but I'm no rocket scientist like you guys when it comes to this stuff, some of these posts are almost jibberish to me

thermoptic · 11-12-2007, 10:40 PM

Quote: Originally Posted by turbocad6

someone say the word & i'll send them a chatbox... anything else I could do to help to I would, but I'm no rocket scientist like you guys when it comes to this stuff, some of these posts are almost jibberish to me

I plan to pick one up very soon. I'm definitely no rocket scientist...too much math and physics for me.

I can spell "plastic welding", but I couldn't tell you the first thing about it.

One of the great things about this forum is the broad range of expertise that all of us bring to the table. Together we can knock out anything.

I researched the controller side in more detail. EE Times has a teardown article discussing the internals. It appears Microsoft used custom chips from National Semiconductor. This increases the chance that the accessory port protocol will be more complex. I also found an article stating the XBOX 360 has security features to lockout unauthorized hardware. I imagine the accessory port interface specification would only be released under NDA.

Xbox controller cuts gaming cord
http://www.eetimes.com/showArticle.j...printable=true

Xbox 360: Only Authorized Third Party Accessories
http://news.teamxbox.com/xbox/8962/X...y-Accessories/

As I don't own an XBOX, I am not privy to the mod/hacker underground sites (either Internet or usenet). I did find this public domain teardown report on the XBOX 360 motherboard, but same-site searches did not yield an equivalent report for the controller side.

XBOX 360 Motherboard Headers and Connectors
http://dwl.xbox-scene.com/tutorial/X...HandC-V1_4.pdf

Has anyone dug into the PC driver side? What does USBView show for a connected XBOX controller? Would the chatpad appear as a secondary device? I found an older site that offered XBOX controller PC drivers before they were available from Microsoft.

XBCD (Dated)
http://www.redcl0ud.com/xbcd.html

XBCD Forums - Lots of info here!!
http://redcl0ud.1.forumer.com/index....opic=1026&st=0

Well, I spend a few hours here and there on this issue. Times up for now. I need to dig into the XBCD forums to see what they have learned. Note the last post was Dec 2006, before chatpad. If we had access to a USB protocol analyzer and the link wasn't encrypted maybe we could hash out a chatpad driver without hardware. That would be ideal but highly unlikely.

I get the feeling that we will have to interface directly to the keypad matrix. I should be able to answer that question by the end of the year as I should have some free time by then...

pokki · 11-13-2007, 12:29 AM

Has anyone tried connecting via PS2 interface instead of USB?

mungewell · 11-13-2007, 02:07 AM

Quote: Originally Posted by pokki

Has anyone tried connecting via PS2 interface instead of USB?

I think you have inadvertantly hit the nail on the head.... As mentioned above M$ is presumably using I2C or SSP between the controller and keyboard, but there's no reason that the PIC couldn't be reprogrammed/replaced to behave as a 'normal' PS2 keyboard and thus make hooking this up to our system easy as pie.

There are lots of examples of PIC PS2 keyboard, google 'PIC PS2 keyboard' if you want to find out more.

Other thoughts from looking at the images:
JP1 header is presumably for programming the PIC in production.
U5/L5 appears to be a switch mode supply, regulation of 3V? or voltage boost for driving the back light LEDs?
Q3,5,6,7 are presumably colum drivers.

What would be really helpful would be a picture of the other side of the board, from this 'we' could work out the matrix and also how the PIC is connected to the matrix and the LED's.

These are on special at local big box store, might pick one up to play with....
Munge.

c0nsumer · 11-13-2007, 10:48 AM

Hey everyone... I just came across this thread after seeing all the referrers hitting my logs. I'm the person who took those photos of disassembling the 360 chat pad. My thoughts are that the easiest thing to do would be to just reprogram the PIC to send keystrokes out via SPI (which is what I believe it uses to connect to the main controller, but I'd have to confirm that) then whatever other device you want (AVR, PIC, whatever has a convenient HID implementation) to convert the SPI data into keystrokes.

Or, if you don't want to rescan the keyboard, you could just use an SPI sniffer (or whatever) to figure out what the chatpad actually sends, then again have something else to turn that into a normal keyboard HID.

As soon as the reverse engineering of the protocol is done (likely trivial, MS has little reason to obfuscate something like this) you could even use a language as simple as mikroBasic, which has a HID library and a lookup table to throw data out as a USB keyboard. If this is your intention, at least.

-Steve

Defiler · 11-13-2007, 11:18 AM

Quote: Originally Posted by c0nsumer

Or, if you don't want to rescan the keyboard, you could just use an SPI sniffer (or whatever) to figure out what the chatpad actually sends, then again have something else to turn that into a normal keyboard HID.
-Steve

Girder anyone?