The SAM4S Xplained Pro kit contains two crystals that can be used as clock sources for the
SAM4S device. Each crystal has a cut-strap next to it that can be used to
measure the oscillator safety factor. This is done by cutting the strap and adding a
resistor across the strap. More information about oscillator allowance and safety factor
can be found in appnote AVR4100.
Table 1. External 32.768kHz
Crystal| Pin on SAM4S |
Function |
|---|
| PA49 |
XIN32 |
| PA48 |
XOUT32 |
Table 2. External 12MHz
Crystal| Pin on SAM4S |
Function |
|---|
| PB9 |
XIN0 |
| PB8 |
XOUT0 |