1. Question: I'm unable to get heart rate information from the GUI.
Answer: The MAXREFDES220 must be flashed with the Maxim supplied algorithm after it is purchased. See the Maxim website for instructions. MAXREFDES220 Design Resources

2. Question: How do I design my own board which will use the smart sensor microcontroller and sensor?
Answer: The schematic for the MAXREFDES220 may be found at the Maxim website listed above. Note that the production part number for the microcontroller is MAX32664GWEA+.

3. Question: Where do I find sample host code to the Smart Sensor?
Answer: The link is below.
Sample Host Code
Here's link to the host code which switches the MAXREFDES220 states from Bootloader/In-App Programming mode to Aplication mode.
SSInterface.cpp
Here's link to the host code which parses the I2c commands that the MAXREFDES220 accepts. Sample commands would be "get_reg ppg 0" to read register 0 of the MAXREFDES220.
SSMAX30101_Comm.cpp

4. Question: Where are the block diagrams, timing diagrams and interface definitions?
Answer: The link is below (at the Mbed Wiki for the MAXREFDES220).
MAXREFDES220 Block Diagram, Timing Diagrams, and Interface Definitions

5. Question: How do I download my own algorithm?
Answer: The MAXREFDES200 Smart Sensor only accepts Maxim supplied algorithms. In order to develop your own sensor hub, please use the MAX32660 microcontroller for the sensor hub.