1 /* mbed Microcontroller Library
2 * Copyright (c) 2006-2013 ARM Limited
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 #include "mbed_assert.h"
17 #include "analogin_api.h"
21 #include "clk_freqs.h"
22 #include "PeripheralPins.h"
24 #define MAX_FADC 6000000
25 #define CHANNELS_A_SHIFT 5
28 void analogin_init(analogin_t *obj, PinName pin) {
29 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
30 MBED_ASSERT(obj->adc != (ADCName)NC);
32 SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
34 uint32_t port = (uint32_t)pin >> PORT_SHIFT;
35 SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
37 uint32_t cfg2_muxsel = ADC_CFG2_MUXSEL_MASK;
38 if (obj->adc & (1 << CHANNELS_A_SHIFT)) {
43 uint32_t PCLK = bus_frequency();
45 for (clkdiv = 0; clkdiv < 4; clkdiv++) {
46 if ((PCLK >> clkdiv) <= MAX_FADC)
49 if (clkdiv == 4) //Set max div
52 ADC0->SC1[1] = ADC_SC1_ADCH(obj->adc & ~(1 << CHANNELS_A_SHIFT));
54 ADC0->CFG1 = ADC_CFG1_ADLPC_MASK // Low-Power Configuration
55 | ADC_CFG1_ADIV(clkdiv & 0x3) // Clock Divide Select: (Input Clock)/8
56 | ADC_CFG1_ADLSMP_MASK // Long Sample Time
57 | ADC_CFG1_MODE(3) // (16)bits Resolution
58 | ADC_CFG1_ADICLK(clkdiv >> 2); // Input Clock: (Bus Clock)/2
60 ADC0->CFG2 = cfg2_muxsel // ADxxb or ADxxa channels
61 | ADC_CFG2_ADHSC_MASK // High-Speed Configuration
62 | ADC_CFG2_ADLSTS(0); // Long Sample Time Select
64 ADC0->SC2 = ADC_SC2_REFSEL(0); // Default Voltage Reference
66 ADC0->SC3 = ADC_SC3_AVGE_MASK // Hardware Average Enable
67 | ADC_SC3_AVGS(0); // 4 Samples Averaged
69 pinmap_pinout(pin, PinMap_ADC);
72 uint16_t analogin_read_u16(analogin_t *obj) {
74 ADC0->SC1[0] = ADC_SC1_ADCH(obj->adc & ~(1 << CHANNELS_A_SHIFT));
76 // Wait Conversion Complete
77 while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
80 return (uint16_t)ADC0->R[0];
83 float analogin_read(analogin_t *obj) {
84 uint16_t value = analogin_read_u16(obj);
85 return (float)value * (1.0f / (float)0xFFFF);