Merge pull request #7118 from photonthunder/sam0_adc_resolution

sam0/adc: assert resolution check fix

cpu/sam0_common/periph/adc.c

@@ -76,7 +76,11 @@ static void _adc_poweroff(void)
 
 static int _adc_configure(adc_res_t res)
 {
-    assert(res >= ADC_RES_8BIT && res <= ADC_RES_12BIT);
+    /* Individual comparison necessary because ADC Resolution Bits are not
+     * numerically in order and 16Bit (averaging - not currently supported)
+     * falls between 12bit and 10bit.  See datasheet for details */
+    assert((res == ADC_RES_8BIT) || (res == ADC_RES_10BIT) ||
+           (res == ADC_RES_12BIT));
     _adc_poweroff();
     if (ADC_0_DEV->CTRLA.reg & ADC_CTRLA_SWRST ||
         ADC_0_DEV->CTRLA.reg & ADC_CTRLA_ENABLE ) {