We are developing a project based on MMA9555L pedometer. We purchased MMA9555L DK and some samples from DIGIKEY distributors.
We notice an over power consumption around 1.6mA with the 4 samples.
Following our MMA9555L Setup:
- VDDA = VDD = 1.8 V
- I2C Communication interface is selected, (a pull-up of 1.8 MΩ is set on RGPIO3/SSB, as with default setting after startup this pin is driven low by MMA) with 10KΩ pull-up resistors on SCL/SDA lines.
We are pretty sure about PCB as when replacing purchased samples by DK’ chip we come back to normal consumption around 85 uA. Also on the DK we place a sample chip and again we observe the over consumption.
From SW point of view, we verify that there is no difference between samples and DK chips (except the device_id)
Following there is a dump of device main application settings (it is corresponding to factory/default configuration)
device_id = x47d341f0, rom_ver = x0101, fw_ver = x0202, hw_ver = x0106, build_ver = x0341
gpio_map /gpio x04 parameters (application = xff, status_bit_position = x00 polarity = 0)
gpio_map /gpio x05 parameters (application = xff, status_bit_position = x00 polarity = 0)
gpio_map /gpio x06 parameters (application = xff, status_bit_position = x00 polarity = 0)
gpio_map /gpio x07 parameters (application = xff, status_bit_position = x00 polarity = 0)
pedometer_configuration/user (gender = 0, height = 175, weight = 80, step_length = 0)
pedometer_configuration/sleep (acceleration_threshold = [0 .. 0], debounce_counter_mode = 0, debounce_counter_threshold = 1)
pedometer_configuration/steps (acceleration_threshold = [1 .., time_window = 4, minimum_count_threshold = 3, coalesce_threshold = 11)
gpio_configuration (direction = x0f, enable = x0f, data = x05)
The only visible difference is the chip MARKING (Note last 3 letters do not math data sheet description)
DK chip (Correct consumption): 263 9555 BXA
samples chip (over consumption): 263 9555 BWL
Apart from the firmware, is there any non-volatile configuration supported by the MMA that can explain observed over consumption.
Is there any explicit difference between BXA / BWL chips.