My board uses a PIC to interface using I2C with an ST accelerometer chip, LIS331DLH. I can read and write to registers okay, at least I can consistently R/W to the control registers for sure. The 8 bytes of X,Y,Z data are extremely noisy though. The low byte in each case is more or less random, the high byte appears to be approximately right, but with some jitter. I've tried different G ranges (2, 4, 8) and different sample rates (50, 100, 400 Hz) and I'm starting to pull my hair out. This is the second prototype board layout, using suggested capacitors etc. All boards act identical. It feels like I'm overlooking some detail in the programming, setup, initialization of the chip, perhaps a detail in my I2C routines, some sort of delay timing issue? I monitor for data ready in the control register before reading. I'm rather at a loss right now. Has anyone encountered similar issues with this chip, or can you offer any suggestions for things to check or to be aware of? Thanks in advance for any help.