Hi Yunlong,
MMA9555L Pedometer application is using directly the AFE Stage 0 Normalized XYZ data, labelled as "output[FRONTEND_Stage_0][XYZ]" registers in product documentation. Consequently modifying the AFE settings such as the configurable low-pass filter will not change the pedometer operation.
As a reminder, the pedometer algorithm is optimized for a 30.5Hz AFE sampling frequency so that one shouldn't be altered.
We recommend to tweak the pedometer application settings (e.g. stepthreshold register) to optimize step detection. If you cannot achieve robust counting, please give us more details (ideally accelerometer data log files) about the tiny wobble you are concerned about so we can take a look at it in order to help.
Regards, Jacques.
