// 1: pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20
_BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1),
// 2: pwmled 3: 1.1V, ADC4 (PA5), single-ended
// 1: pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20
_BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1),
// 2: pwmled 3: 1.1V, ADC4 (PA5), single-ended