We have purchased a total of seven ADcmXL3021 sensors over time in different batches.
For our application, we designed an in-house PCB that interfaces the ADcmXL3021 with an ESP32-S3 microcontroller. The same PCB design and the same firmware are used for all sensors.
In our firmware, the RT_CTRL register is configured with the value 0x0080, which according to our understanding should set the device to an output data rate of 20,000 SPS in RTS mode. Also register REC_CTRL is configured with the value 0x1103, which should put the sensor in RTS mode.
However, with two of the seven ADcmXL3021 sensors, we observe a different behavior. When these sensors are connected to the exact same hardware and operated with the exact same firmware, a logic analyzer shows an output data rate of approximately 220,000 SPS instead of 20,000 SPS.
The serial output of the ESP32-S3 give the following information about the two not working ADcmXL3021 sensors:
PROD_ID=0x0BCD, SERIAL=0x00EC, REV_DAY=0x0326, YEAR_MON=0x1902
The remaining five sensors operate as expected and output data at approximately 20,000 SPS.
Since the hardware and firmware are identical for all tested units, we are wondering whether this behavior could indicate:
- a device configuration issue that we may have overlooked,
- a difference in device revision,
- a calibration or factory-programmed setting,
- or a possible device defect.
Has any one encountered similar behavior before, or are there any registers or diagnostics that you would recommend checking?
