2.1 Calibration Clock Accuracy

The accuracy of the calibration is highly dependent on the accuracy of the external calibration clock. The calibration clock frequency generated by the AVR tools may vary. It is therefore important to measure the exact frequency of the signal on the JTAG TDI pin, and update the corresponding reference clock frequency value in the main.c file. Since resonators are dependent on both operating voltage and temperature, the frequency of the calibration clock should be measured when these parameters equal the conditions during calibration.