1 files changed, 116 insertions, 0 deletions
diff --git a/atmel-samd/common-hal/analogio/AnalogIn.c b/atmel-samd/common-hal/analogio/AnalogIn.c
new file mode 100644
index 000000000..59ea3b899
--- /dev/null
+++ b/atmel-samd/common-hal/analogio/AnalogIn.c
@@ -0,0 +1,116 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "common-hal/analogio/AnalogIn.h"
+
+#include <string.h>
+
+#include "py/gc.h"
+#include "py/nlr.h"
+#include "py/runtime.h"
+#include "py/binary.h"
+#include "py/mphal.h"
+#include "shared-bindings/analogio/AnalogIn.h"
+
+#include "asf/sam0/drivers/adc/adc.h"
+#include "samd21_pins.h"
+
+// Number of active ADC channels.
+volatile uint8_t active_channel_count;
+struct adc_module *adc_instance = NULL;
+
+void common_hal_analogio_analogin_construct(analogio_analogin_obj_t* self,
+        const mcu_pin_obj_t *pin) {
+    if (!pin->has_adc) {
+        // No ADC function on that pin
+        mp_raise_ValueError("Pin does not have ADC capabilities");
+    }
+
+    self->pin = pin;
+
+    if (adc_instance == NULL) {
+        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_16BIT;
+        config_adc.clock_prescaler = ADC_CLOCK_PRESCALER_DIV128;
+
+        // Allocate the instance on the heap so we only use the memory when we
+        // need it.
+        adc_instance = gc_alloc(sizeof(struct adc_module), false);
+
+        adc_init(adc_instance, ADC, &config_adc);
+    }
+
+    self->adc_instance = adc_instance;
+    active_channel_count++;
+}
+
+void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
+    active_channel_count--;
+    if (active_channel_count == 0) {
+        adc_reset(adc_instance);
+        gc_free(adc_instance);
+        // Set our reference to NULL so the GC doesn't mistakenly see the
+        // pointer in memory.
+        adc_instance = NULL;
+    }
+    reset_pin(self->pin->pin);
+}
+
+void analogin_reset() {
+    if (adc_instance != NULL) {
+        adc_reset(adc_instance);
+        adc_instance = NULL;
+    }
+    active_channel_count = 0;
+}
+
+uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
+    adc_set_positive_input(adc_instance, self->pin->adc_input);
+
+    adc_enable(adc_instance);
+    adc_start_conversion(adc_instance);
+
+    uint16_t data;
+    enum status_code status = adc_read(adc_instance, &data);
+    while (status == STATUS_BUSY) {
+      status = adc_read(adc_instance, &data);
+    }
+    if (status == STATUS_ERR_OVERFLOW) {
+      // TODO(tannewt): Throw an error.
+    }
+
+    adc_disable(adc_instance);
+    return data;
+}
+
+float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
+    return 3.3f;
+}