The SpO2 % and HR calculation is done in the Windows application with the raw data and is not performed in the firmware. The MAXREFDES220 is likely the best system to obtain an algorithm which can be integrated into the customers end system, but this reference design does not support BLE. There is the MAXREFDES101 which supports wrist HR and BLE, but does not support SpO2. The MAXREFDES100 does not have an on chip algorithm that calculates SpO2 or HR, it just provides raw data that the user can use to develop their own algorithm.