Is anyone still working on this? I've begun picking parts to build a carputer and agree this keypad would work nicely. Picked up a chatpad yesterday and tore it apart. First time on the forum...
I've dug into the serial connection between then chatpad and the controller with a digital o-scope while its connected to my xbox360 wirelessly. Really my first attempt at figuring a protocol out like this, so feel free to jump in.
Here are some of myfindings:
-Bits are ~52us wide which tells me 19200 baud rate. Still haven't put my finger on the exact settings beyond the baud rate.
-The controller sends a series of initialization "packets", 3 total and they vary between 47 and 49 bits, or possibly two subsets close together making 6 total packets. I haven't decoded them
-The initialization packets come in the same order each time.
-While the controller is connected to the xbox, the controller sends a packet every second, again 47-49 bits long. This packet is not the same each time, there are 4 total and they repeat every 4 seconds.
-The chatpad responds with a series of 11 packets, a group of 4 after the first packet sent by the controller, a group of 7, then it goes into idle mode mentioned next.
-At idle, the chatpad responds with a series of 4 identical packets each second. They are separated by ~40ms and consist of ~105 bits total, more likely divided into 18 bits, a pause, then another 57 bits. Each of the 4 packets are the same.
-When a key is pressed, the pic waits until the idle packets are transmitted, then sends a series of 8 packets representing the key press. Each packet looks similar in length to the idle packets.
I've never probed a USB port during enumeration, I will look into that next as this seems extremely complicated for a simple serial connection. Anyone with USB knowledge please weigh in.
Here are some screen shots (literally) from the scope.
1st packets, blue is the chatpad Rx, Yellow is Tx.
2nd set of packets
3rd set of packets
4th set of packets, really the first "idle" sequence