I have taken apart an old non-functional Lenovo IdeaCentre (B320) computer.
I would like to get the glass touch panel to 'work' (I would consider anything from simply being able to sniff the x,y coordinates to be 'working').
There is a single cable coming from the glass, this cable plugs into a module. The module has only one other connection. This connection has four wires and is connected to the motherboard of the computer. The black and red wires are ground and 5V respectively, this I confirmed by powering on the computer and measuring. The remaining two wires are a mystery, they are (for what it's worth) brown and orange.
Following the traces on the module, I can see they are connected to an STM32F102C6 (LQFP48). The two wires are connected to pin 32 (brown) and 33 (orange). I downloaded the datasheet for the MCU, from this I can see pin 32, 33 corresponds to PA11 and PA12 respectively.
PA11 has the alternate function 'USART1_CTS/USB_DM'
PA12 has the alternate function 'USART1_RTS/USB_DP'
I did some googling and it seems that CTS and RTS are only used for data flow control, considering there are no other data wires I assumed the USB protocol is the most likely (even though the wire colors are not conventional to USB). I wired up a USB cable and plugged it into my computer and nothing happened (absolutely nothing).
I'm stuck for ideas now. Could it be performing some kind of communication over the USART pin functions or possibly even some kind of bit-banged protocol over the GPIO's? Perhaps the module is dead and that's why the USB isn't detected by the computer.
What further steps could I take to reverse engineer this module?