3.1.1 Xplained Mini Clock Output

The mEDBG outputs its CPU clock on a pin. This clock pin is connected to the ATmega328P clock input and is used to have a synchronous clock with the mEDBG to enable debugging through debugWIRE.

To disconnect the external clock to the ATmega328P, a 0Ω resistor or strap has to be removed from the footprint, as shown in the figure below (R109).
Figure 3-1. External Clock Footprint

The mEDBG CPU clock frequency depends on the selected voltage, see the table below.

Table 3-2. CPU Clock vs. Voltage
Target VoltagemEDBG CPU Clock
3.3V8 MHz
5.0V16 MHz