Diff: targets/TARGET_NXP/TARGET_LPC15XX/analogin_api.c

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC15XX/analogin_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,154 @@
+/* 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_12BIT_RANGE             0xFFF
+
+#define ADC_RANGE    ADC_12BIT_RANGE
+
+static const PinMap PinMap_ADC[] = {
+    {P0_8 , ADC0_0, 0},
+    {P0_7 , ADC0_1, 0},
+    {P0_6 , ADC0_2, 0},
+    {P0_5 , ADC0_3, 0},
+    {P0_4 , ADC0_4, 0},
+    {P0_3 , ADC0_5, 0},
+    {P0_2 , ADC0_6, 0},
+    {P0_1 , ADC0_7, 0},
+    {P1_0 , ADC0_8, 0},
+    {P0_31, ADC0_9, 0},
+    {P0_0 , ADC0_10,0},
+    {P0_30, ADC0_11,0},
+    {P1_1 , ADC1_0, 0},
+    {P0_9 , ADC1_1, 0},
+    {P0_10, ADC1_2, 0},
+    {P0_11, ADC1_3, 0},
+    {P1_2 , ADC1_4, 0},
+    {P1_3 , ADC1_5, 0},
+    {P0_13, ADC1_6, 0},
+    {P0_14, ADC1_7, 0},
+    {P0_15, ADC1_8, 0},
+    {P0_16, ADC1_9, 0},
+    {P1_4 , ADC1_10,0},
+    {P1_5 , ADC1_11,0},
+};
+
+void analogin_init(analogin_t *obj, PinName pin) {
+    obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
+    MBED_ASSERT(obj->adc != (ADCName)NC);
+
+    uint32_t port = (pin >> 5);
+    // enable clock for GPIOx
+    LPC_SYSCON->SYSAHBCLKCTRL0 |= (1UL << (14 + port));
+    // pin enable
+    LPC_SWM->PINENABLE0 &= ~(1UL << obj->adc);
+    // configure GPIO as input
+    LPC_GPIO_PORT->DIR[port] &= ~(1UL << (pin & 0x1F));
+    
+    // power up ADC
+    if (obj->adc < ADC1_0)
+    {
+        // ADC0
+        LPC_SYSCON->PDRUNCFG &= ~(1 << 10);
+        LPC_SYSCON->SYSAHBCLKCTRL0 |= (1 << 27);
+    }
+    else {
+        // ADC1
+        LPC_SYSCON->PDRUNCFG &= ~(1 << 11);
+        LPC_SYSCON->SYSAHBCLKCTRL0 |= (1 << 28);
+    }
+
+    __IO LPC_ADC0_Type *adc_reg = (obj->adc < ADC1_0) ? (__IO LPC_ADC0_Type*)(LPC_ADC0) : (__IO LPC_ADC0_Type*)(LPC_ADC1);
+
+    // 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);
+
+    // Sampling clock: SystemClock divided by 1
+    adc_reg->CTRL = 0;
+}
+
+static inline uint32_t adc_read(analogin_t *obj) {
+    uint32_t channels;
+
+    __IO LPC_ADC0_Type *adc_reg = (obj->adc < ADC1_0) ? (__IO LPC_ADC0_Type*)(LPC_ADC0) : (__IO LPC_ADC0_Type*)(LPC_ADC1);
+
+    if (obj->adc >= ADC1_0)
+        channels = ((obj->adc - ADC1_0) & 0x1F);
+    else
+        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);
+}