HackedMouseUsb

intro

i pretty much abandoned the HackedMouse as soon as i figured out how to control it. I got busy with other projects and just never went back to it. i also came into an old optical USB mouse. seeing as how my new laptop doesn't have PS/2 and does have USB i figured i might as well attack this one instead. I can't tell you much about it because all i have is the circuit board. i took it apart a while ago and threw out everything else. i know it had a scroll wheel with click and 4 buttons. i am guessing that most cheap optical mice are pretty much the same though.

• HmuMouseResearch
• HmuSoftwareSpec
• HmuMouseSniffer

It appears that the clock may be too fast for the avronics board to keep up with. The mouse is also causing the avronics board to reboot often. I need to get some time on the scope and add a pullup to the /RESET pin on the atmega32 to hopefully fix this.

implementation

Serial Interface

Serial Bus Sequence

• SCK High at system power up
• SCK High after data transfer

• SCK falling edge
• SDIO data latches
• SCK rising edge
• SDIO read/write

Serial Timing

I need to sniff the existing commands in order to fully emulate the optical sensor. I bit bang the interface to keep it simple.

• Data read on rising edge
• Data latched on falling edge
• SCK is driven by the USB chip
• leading 1 is a write command
• leading 0 is a read command
• all communication is driven by the master (USB chip)

Serial Registers

Address	Register
0x00	Product_ID
0x01	Revision_ID
0x02	Motion
0x03	Delta_X
0x04	Delta_Y
0x05	SQUAL
0x06	Average_Pixel
0x07	Maximum_Pixel
0x08	Reserved
0x09	Reserved
0x0a	Configuration_bits
0x0b	Reserved
0x0c	Data_Out_Lower
0x0d	Data_Out_Upper
0x0e	Shutter_Lower
0x0f	Shutter_Upper
0x10	Frame_Period_Lower
0x11	Frame_Period_Upper

Hardware

the optical sensor is disconnected from the USB controller. in it's place the AVRonics controller is wired into the SCK and SDIO serial interface of the USB controller. it is now possible to control the x,y position of the cursor with the AVRonics board.

new pointing device

the first app will be a RS232 interface into the 'mouse' so i should be able to control the cursor with minicom.

-- ChristopherPepe - 21 Aug 2006