part identification question here. It comes from an Xfinity XR11 Remote. It’s used to detect acceleration when picking up the remote.
The footprint and part/trace placement heavily matches what I’d expect for an STM accelerometer but the register map just doesn’t fit. Specifically one of these.
The package reads 31UHQ and is a 2mmx2mm LGA package. It seems that the 4x3 pin layout has a standard pin configuration of two interrupt outputs and I2C/SPI pin locations.
It has registers starting at 0x00 and some of the reads and writes I see from a logic analyzer are to addresses that the datasheet claims are “reserved”. For example, bits 0, 1, and 2 on register 0x17 enable the X, Y, and Z axis. I can provide a full register dump if needed.
If it helps, here are the ins and outs. All resistors are 0ohm bridges.
- R11 = SCL
- R20 = SDA
- TP50 = VCC (2v5)
- TP1 = Interrupt (not sure if INT0 or INT1)
- TP26 = Unknown
- TP27 = Unknown
Start-up sequence: (Op, Reg, Data)
- W 17 07
- W 19 02
- W 25 04
- W 26 06
- W 36 07
- W 20 08