4.2.4 VREF Header

SAM C21 Xplained Pro has a 6-pin header labeled VREF on the board. This header can be used to select / apply a voltage reference to the ADC, DAC, and SDADC. Jumpers can be used to tie SADC VREF and ADC/DAC VREFT to the kit target voltage from pin 1-3 and 2-4, or external voltages can be applied across pin 3-5 and 4-6.

Table 4-10. VREF Header
VREF header pinPin / NetFunction
1VCC_AREF_P3V3_P5V0Filtered kit target voltage
2VCC_AREF_P3V3_P5V0Filtered kit target voltage
3PA04SDADC voltage reference
4PA03ADC / DAC voltage reference
5GNDGround
6GNDGround