Diff: targets/hal/TARGET_NXP/TARGET_LPC43XX/analogin_api.c

Revision:

20:4263a77256ae

Child:

227:7bd0639b8911

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_NXP/TARGET_LPC43XX/analogin_api.c	Tue Sep 10 15:14:19 2013 +0300
@@ -0,0 +1,129 @@
+/* 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.
+ *
+ * Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
+ */
+#include "analogin_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+#include "error.h"
+
+#define ANALOGIN_MEDIAN_FILTER      1
+
+static inline int div_round_up(int x, int y) {
+  return (x + (y - 1)) / y;
+}
+
+// ToDo: Add support for ADC1
+static const PinMap PinMap_ADC[] = {
+    {P_ADC0, ADC0_0, 0x08},
+    {P_ADC1, ADC0_1, 0x07},
+    {P_ADC2, ADC0_2, 0x01},
+    {P_ADC3, ADC0_3, 0x08},
+    {P_ADC4, ADC0_4, 0x08},
+    {P_ADC5, ADC0_5, 0x08},
+    {NC   , NC    , 0   }
+};
+
+void analogin_init(analogin_t *obj, PinName pin) {
+    uint8_t num, chan;
+
+    obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
+    if (obj->adc == (uint32_t)NC) {
+        error("ADC pin mapping failed");
+    }
+
+
+    // Configure the pin as GPIO input
+    if (pin < SFP_AIO0) {
+        pin_function(pin, (SCU_PINIO_PULLNONE | 0x0));
+        pin_mode(pin, PullNone);
+        num = (uint8_t)(obj->adc) / 8; // Heuristic?
+        chan = (uint8_t)(obj->adc) % 7;
+    } else {
+        num = MBED_ADC_NUM(pin);
+        chan = MBED_ADC_CHAN(pin);
+    }
+
+    // Calculate minimum clock divider
+    //  clkdiv = divider - 1
+		uint32_t PCLK = SystemCoreClock;
+    uint32_t adcRate = 400000;
+    uint32_t clkdiv = div_round_up(PCLK, adcRate) - 1;
+    
+    // Set the generic software-controlled ADC settings
+    LPC_ADC0->CR = (0 << 0)      // SEL: 0 = no channels selected
+                  | (clkdiv << 8) // CLKDIV:
+                  | (0 << 16)     // BURST: 0 = software control
+                  | (1 << 21)     // PDN: 1 = operational
+                  | (0 << 24)     // START: 0 = no start
+                  | (0 << 27);    // EDGE: not applicable
+
+    // Select ADC on analog function select register in SCU
+    LPC_SCU->ENAIO[num] |= 1UL << chan;
+}
+
+static inline uint32_t adc_read(analogin_t *obj) {
+    // Select the appropriate channel and start conversion
+    LPC_ADC0->CR &= ~0xFF;
+    LPC_ADC0->CR |= 1 << (int)obj->adc;
+    LPC_ADC0->CR |= 1 << 24;
+
+    // Repeatedly get the sample data until DONE bit
+    unsigned int data;
+    do {
+        data = LPC_ADC0->GDR;
+    } while ((data & ((unsigned int)1 << 31)) == 0);
+
+    // Stop conversion
+    LPC_ADC0->CR &= ~(1 << 24);
+
+    return (data >> 6) & ADC_RANGE; // 10 bit
+}
+
+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 << 6) | ((value >> 4) & 0x003F); // 10 bit
+}
+
+float analogin_read(analogin_t *obj) {
+    uint32_t value = adc_read_u32(obj);
+    return (float)value * (1.0f / (float)ADC_RANGE);
+}