2.1.1 FSFEB Calibration

It is highly recommended that FSFEB is calibrated on the first start-up, or if the behavior of FSFEB is not as expected.

The calibration routine will adjust the trigger level for the fault detection on the fan. Calibration is needed since the fan current consumption can vary based on temperature, supply voltage, and from device to device.

The calibration routine takes about eight seconds and can be started like this:

• Set operating voltage to POR
• Push and hold all three buttons
• Set operating voltage to Normal
• Release buttons

When FSFEB enters calibration mode, the Application heartbeat LED is turned ON (without blinking) and the fan will start. When calibration is complete, the calibration data is stored in EEPROM. These values will be used the next time ATtiny3217 is restarted.

A software reset occurs when calibration is complete, thus forcing a load of the new calibration data.