Diff: mbed-dev/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/analogin_api.c

Revision:

18:6a4db94011d3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-dev/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/analogin_api.c	Sun May 14 23:18:57 2017 +0000
@@ -0,0 +1,81 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "mbed_assert.h"
+#include "analogin_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+
+#define ANALOGIN_MEDIAN_FILTER      1
+#define ADC_10BIT_RANGE             0x3FF
+#define ADC_RANGE    ADC_10BIT_RANGE
+
+static const PinMap PinMap_ADC[] = {
+    {P0_1, ADC0_0, 4},
+    {P0_2, ADC0_0, 8},
+    {P0_3, ADC0_0, 16},
+    {P0_4, ADC0_0, 32},
+    {P0_5, ADC0_0, 64},
+    {P0_6, ADC0_0, 128},
+#ifndef TARGET_NRF51_DONGLE
+    {P0_26, ADC0_0, 1},
+    {P0_27, ADC0_0, 2},
+#endif
+    {NC, NC, 0}
+};
+
+void analogin_init(analogin_t *obj, PinName pin)
+{
+    int analogInputPin = 0;
+    const PinMap *map  = PinMap_ADC;
+
+    obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC); //(NRF_ADC_Type *)
+    MBED_ASSERT(obj->adc != (ADCName)NC);
+
+    while (map->pin != NC) {
+        if (map->pin == pin) {
+            analogInputPin = map->function;
+            break;
+        }
+        map++;
+    }
+    obj->adc_pin = (uint8_t)analogInputPin;
+
+    NRF_ADC->ENABLE = ADC_ENABLE_ENABLE_Enabled;
+    NRF_ADC->CONFIG = (ADC_CONFIG_RES_10bit << ADC_CONFIG_RES_Pos) |
+                      (ADC_CONFIG_INPSEL_AnalogInputOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos) |
+                      (ADC_CONFIG_REFSEL_SupplyOneThirdPrescaling << ADC_CONFIG_REFSEL_Pos) |
+                      (analogInputPin << ADC_CONFIG_PSEL_Pos) |
+                      (ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos);
+}
+
+uint16_t analogin_read_u16(analogin_t *obj)
+{
+    NRF_ADC->CONFIG     &= ~ADC_CONFIG_PSEL_Msk;
+    NRF_ADC->CONFIG     |= obj->adc_pin << ADC_CONFIG_PSEL_Pos;
+    NRF_ADC->EVENTS_END  = 0;
+    NRF_ADC->TASKS_START = 1;
+
+    while (!NRF_ADC->EVENTS_END) {
+    }
+
+    return (uint16_t)NRF_ADC->RESULT; // 10 bit
+}
+
+float analogin_read(analogin_t *obj)
+{
+    uint16_t value = analogin_read_u16(obj);
+    return (float)value * (1.0f / (float)ADC_RANGE);
+}