Fix up Analog classes: unify them at 16 bits and adds reference_voltage member

to make for easy conversion. Fixes #14.

2 files changed, 9 insertions, 4 deletions

diff --git a/atmel-samd/common-hal/nativeio/AnalogIn.c b/atmel-samd/common-hal/nativeio/AnalogIn.c
index 592ba4ca8..0d5f98310 100644
--- a/atmel-samd/common-hal/nativeio/AnalogIn.c
+++ b/atmel-samd/common-hal/nativeio/AnalogIn.c
@@ -47,10 +47,10 @@ void common_hal_nativeio_analogin_construct(nativeio_analogin_obj_t* self,
     struct adc_config config_adc;
     adc_get_config_defaults(&config_adc);
 
+    config_adc.reference = ADC_REFERENCE_INTVCC1;
+    config_adc.gain_factor = ADC_GAIN_FACTOR_DIV2;
     config_adc.positive_input = self->pin->adc_input;
-    config_adc.resolution = ADC_RESOLUTION_CUSTOM;
-    config_adc.accumulate_samples = ADC_ACCUMULATE_SAMPLES_16;
-    config_adc.divide_result = ADC_DIVIDE_RESULT_16;
+    config_adc.resolution = ADC_RESOLUTION_16BIT;
     config_adc.clock_prescaler = ADC_CLOCK_PRESCALER_DIV128;
 
     adc_init(&self->adc_instance, ADC, &config_adc);
@@ -82,3 +82,7 @@ uint16_t common_hal_nativeio_analogin_get_value(nativeio_analogin_obj_t *self) {
     adc_disable(&self->adc_instance);
     return data;
 }
+
+float common_hal_nativeio_analogin_get_reference_voltage(nativeio_analogin_obj_t *self) {
+    return 3.3f;
+}
diff --git a/atmel-samd/common-hal/nativeio/AnalogOut.c b/atmel-samd/common-hal/nativeio/AnalogOut.c
index 958eb7e6a..df4cc44a2 100644
--- a/atmel-samd/common-hal/nativeio/AnalogOut.c
+++ b/atmel-samd/common-hal/nativeio/AnalogOut.c
@@ -67,5 +67,6 @@ void common_hal_nativeio_analogout_deinit(nativeio_analogout_obj_t *self) {
 
 void common_hal_nativeio_analogout_set_value(nativeio_analogout_obj_t *self,
         uint16_t value) {
-    dac_chan_write(&self->dac_instance, DAC_CHANNEL_0, value);
+    // Input is 16 bit but we only support 10 bit so we shift the input.
+    dac_chan_write(&self->dac_instance, DAC_CHANNEL_0, value >> 6);
 }