As of February 2, 2026, the NXP MEMS Sensor products have been transferred to STMicroelectronics. For details on the transferred products, see this page. Please reach out to STMicroelectronics for further information.
unfortunately there is no a bare metal example for the PCF2131, but please refer to the PCF2131-ARD, which can be used with one of our MCU boards, and a binary firmware.