GEM Module Hardware Integration Guide
Version 0.3
Wahoo Fitness
9
90 West Wieuca Road, Suite 110
Atlanta, GA 30342
www.wahoofitness.com
1-‐877-‐978-‐1112
Electrical Specifications
Absolute Maximum ratings
Maximum and minimum ratings for digital and analog pins are listed below.
Parameter
Min
Max
VCC Voltage
-‐0.3V
+3.9V
Voltage at VIO
-‐0.3V
VCC+.3V
Storage Temperature -‐40C
+85C
Recommended Operating Parameters
Parameter
Min
Typical
Max
VCC
1.8V
3.0V
+3.6V
VCC maximum ripple
10mV
VCC Rise time
100mS
Operating Temperature @ 3.3V -‐40C
+85C
Design Considerations
The GEM module has been designed for easy integration into OEM applications requiring
minimal additional componentry. The following section provides suggestions to ensure
successful design in of the GEM module.
Hardware
VCC
Ensure the power source operating range and noise is within the specified limits for the
GEM module and filter capacitors are incorporated as needed. The GEM module includes
decoupling capacitors for circuits within the module. External circuits sharing the same
power source should also be decoupled locally at connections to VCC and GND.
Updating Module Firmware
The GEM module firmware can be updated over the air using the Wahoo utility application.
The Wahoo utility application can be downloaded here:
www.xxxx.yyy.com
The GEM module firmware can also be updated through the Serial Wire Debug interface.
The following circuit example provides a reference for developers wanting an alternative to
programming the GEM module over the air:
