I want to experiment with turning a salvaged laptop keyboard module into a USB HID keyboard. My test subject is this keyboard pulled from an Acer Aspire Switch 10. I have successfully unsoldered its connector in the hopes I can solder it onto a breakout board I had ordered. While I wait for the board to be shipped to me, I can do a little scouting.

The easiest observation was that 2 out of 26 pins appear to be unused. They are present at the flex cable connector but immediately disappear into nothingness.

The remaining 24 wires are seen going into the keyboard module underneath a piece of black fabric tape. Peeling that tape off may gain more insight, but I'm not going to. Flex cables can only flex a finite number of times before something breaks, so I'm trying to keep handling and manipulation to a minimum.

Examining the circuit board, I looked for traces that are significantly wider than others or maybe wires that span multiple pins in parallel. Both are typical indications of power or ground wires, but I didn't see anything of the sort. I then looked for components like decoupling capacitors or current-limiting resistors, and didn't notice any good candidates either. This is consistent with my memory this keyboard was not backlit.

Looking on the back side, I see very few wires and they are mostly consistent with wires jumping over other perpendicular wires on the front. Not all of the vias lined up with traces I could see, which would be consistent with a circuit board with more than two layers. Though there are traces I couldn't see, I think it is possible all 24 wires are connected directly to the chip adjacent to the now-unsoldered connector.

I read the chip marking as IT8595E-128 and the logo matches that of Taiwan-based ITE Tech, Inc. But there's no IT8595E-128 listed on their product website today. The closest I found is an IT8596 under "Notebook product line", advertised to be a laptop peripheral controller. Sounds about right, but there's no datasheet download for me to see if it might be a sibling of this IT8595. Perhaps IT8595 is a discontinued product, or perhaps it was a custom design exclusive to Acer. Either way, I'm not going to get any more information here. To get any more information on how this keyboard module is wired, I will need to wait for my adapter board to arrive.