Diff: targets/TARGET_NXP/TARGET_LPC82X/analogin_api.c

Revision:

149:156823d33999

Parent:

144:ef7eb2e8f9f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC82X/analogin_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,131 @@
+/* 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"
+#include "PeripheralNames.h"
+
+#if DEVICE_ANALOGIN
+
+#define ANALOGIN_MEDIAN_FILTER      1
+
+#define ADC_RANGE    0xFFF
+
+static const PinMap PinMap_ADC[] = {
+    {P0_7 , ADC_0, 0},
+    {P0_6 , ADC_1, 0},
+    {P0_14, ADC_2, 0},
+    {P0_23, ADC_3, 0},
+    {P0_22, ADC_4, 0},
+    {P0_21, ADC_5, 0},
+    {P0_20, ADC_6, 0},
+    {P0_19, ADC_7, 0},
+    {P0_18, ADC_8, 0},
+    {P0_17, ADC_9, 0},
+    {P0_13, ADC_10,0},
+    {P0_4 , ADC_11,0},
+};
+
+void analogin_init(analogin_t *obj, PinName pin)
+{
+    obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
+    MBED_ASSERT(obj->adc != (ADCName)NC);
+
+    LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 6);
+    // pin enable
+    LPC_SWM->PINENABLE0 &= ~(1UL << (13 + obj->adc));
+    // configure GPIO as input
+    LPC_GPIO_PORT->DIR0 &= ~(1UL << (pin >> PIN_SHIFT));
+
+    LPC_SYSCON->PDRUNCFG &= ~(1 << 4);
+    LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 24);
+
+    __IO LPC_ADC_Type *adc_reg = LPC_ADC;
+
+    // determine the system clock divider for a 500kHz ADC clock during calibration
+    uint32_t clkdiv = (SystemCoreClock / 500000) - 1;
+
+    // perform a self-calibration
+    adc_reg->CTRL = (1UL << 30) | (clkdiv & 0xFF);
+    while ((adc_reg->CTRL & (1UL << 30)) != 0);
+}
+
+static inline uint32_t adc_read(analogin_t *obj)
+{
+    uint32_t channels;
+    __IO LPC_ADC_Type *adc_reg = LPC_ADC;
+
+    channels = (obj->adc & 0x1F);
+
+    // select channel
+    adc_reg->SEQA_CTRL &= ~(0xFFF);
+    adc_reg->SEQA_CTRL |= (1UL << channels);
+
+    // start conversion and sequence enable
+    adc_reg->SEQA_CTRL |= ((1UL << 26) | (1UL << 31));
+
+    // Repeatedly get the sample data until DONE bit
+    volatile uint32_t data;
+    do {
+        data = adc_reg->SEQA_GDAT;
+    } while ((data & (1UL << 31)) == 0);
+
+    // Stop conversion
+    adc_reg->SEQA_CTRL &= ~(1UL << 31);
+
+    return ((data >> 4) & ADC_RANGE);
+}
+
+static inline void order(uint32_t *a, uint32_t *b)
+{
+    if (*a > *b) {
+        uint32_t t = *a;
+        *a = *b;
+        *b = t;
+    }
+}
+
+static inline uint32_t adc_read_u32(analogin_t *obj)
+{
+    uint32_t value;
+#if ANALOGIN_MEDIAN_FILTER
+    uint32_t v1 = adc_read(obj);
+    uint32_t v2 = adc_read(obj);
+    uint32_t v3 = adc_read(obj);
+    order(&v1, &v2);
+    order(&v2, &v3);
+    order(&v1, &v2);
+    value = v2;
+#else
+    value = adc_read(obj);
+#endif
+    return value;
+}
+
+uint16_t analogin_read_u16(analogin_t *obj)
+{
+    uint32_t value = adc_read_u32(obj);
+    return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
+}
+
+float analogin_read(analogin_t *obj)
+{
+    uint32_t value = adc_read_u32(obj);
+    return (float)value * (1.0f / (float)ADC_RANGE);
+}
+
+#endif