Diff: mbed-dev/targets/TARGET_Freescale/TARGET_K20XX/analogin_api.c

Revision:

18:6a4db94011d3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-dev/targets/TARGET_Freescale/TARGET_K20XX/analogin_api.c	Sun May 14 23:18:57 2017 +0000
@@ -0,0 +1,78 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 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 "clk_freqs.h"
+#include "PeripheralPins.h"
+
+#define MAX_FADC        6000000
+
+void analogin_init(analogin_t *obj, PinName pin) {
+    obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
+    MBED_ASSERT(obj->adc != (ADCName)NC);
+
+    SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
+
+    uint32_t port = (uint32_t)pin >> PORT_SHIFT;
+    SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
+
+    // bus clk
+    uint32_t PCLK = bus_frequency();
+    uint32_t clkdiv;
+    for (clkdiv = 0; clkdiv < 4; clkdiv++) {
+        if ((PCLK >> clkdiv) <= MAX_FADC)
+            break;
+    }
+    if (clkdiv == 4)                    //Set max div
+        clkdiv = 0x7;
+
+    ADC0->SC1[1] = ADC_SC1_ADCH(obj->adc);
+
+    ADC0->CFG1 = ADC_CFG1_ADLPC_MASK    // Low-Power Configuration
+               | ADC_CFG1_ADIV(clkdiv & 0x3)       // Clock Divide Select
+               | ADC_CFG1_ADLSMP_MASK   // Long Sample Time
+               | ADC_CFG1_MODE(3)       // (16)bits Resolution
+               | ADC_CFG1_ADICLK(clkdiv >> 2);    // Input Clock
+
+    ADC0->CFG2 = ADC_CFG2_MUXSEL_MASK   // ADxxb or ADxxa channels
+               | ADC_CFG2_ADHSC_MASK    // High-Speed Configuration
+               | ADC_CFG2_ADLSTS(0);    // Long Sample Time Select
+
+    ADC0->SC2 = ADC_SC2_REFSEL(0);      // Default Voltage Reference
+
+    ADC0->SC3 = ADC_SC3_AVGE_MASK       // Hardware Average Enable
+              | ADC_SC3_AVGS(0);        // 4 Samples Averaged
+
+    pinmap_pinout(pin, PinMap_ADC);
+}
+
+uint16_t analogin_read_u16(analogin_t *obj) {
+    // start conversion
+    ADC0->SC1[0] = ADC_SC1_ADCH(obj->adc);
+
+    // Wait Conversion Complete
+    while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
+
+    return (uint16_t)ADC0->R[0];
+}
+
+float analogin_read(analogin_t *obj) {
+    uint16_t value = analogin_read_u16(obj);
+    return (float)value * (1.0f / (float)0xFFFF);
+}