erkin yucel / mbed-os

mbed os with nrf51 internal bandgap enabled to read battery level

Dependents:   BLE_file_test BLE_Blink ExternalEncoder

targets/TARGET_Freescale/TARGET_KLXX/analogin_api.c@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

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elessair 0:f269e3021894 1 /* mbed Microcontroller Library
elessair 0:f269e3021894 2 * Copyright (c) 2006-2013 ARM Limited
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 5 * you may not use this file except in compliance with the License.
elessair 0:f269e3021894 6 * You may obtain a copy of the License at
elessair 0:f269e3021894 7 *
elessair 0:f269e3021894 8 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 9 *
elessair 0:f269e3021894 10 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 11 * distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 13 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 14 * limitations under the License.
elessair 0:f269e3021894 15 */
elessair 0:f269e3021894 16 #include "mbed_assert.h"
elessair 0:f269e3021894 17 #include "analogin_api.h"
elessair 0:f269e3021894 18
elessair 0:f269e3021894 19 #include "cmsis.h"
elessair 0:f269e3021894 20 #include "pinmap.h"
elessair 0:f269e3021894 21 #include "clk_freqs.h"
elessair 0:f269e3021894 22 #include "PeripheralPins.h"
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 #define MAX_FADC 6000000
elessair 0:f269e3021894 25 #define CHANNELS_A_SHIFT 5
elessair 0:f269e3021894 26
elessair 0:f269e3021894 27
elessair 0:f269e3021894 28 void analogin_init(analogin_t *obj, PinName pin) {
elessair 0:f269e3021894 29 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
elessair 0:f269e3021894 30 MBED_ASSERT(obj->adc != (ADCName)NC);
elessair 0:f269e3021894 31
elessair 0:f269e3021894 32 SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
elessair 0:f269e3021894 33
elessair 0:f269e3021894 34 uint32_t port = (uint32_t)pin >> PORT_SHIFT;
elessair 0:f269e3021894 35 SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
elessair 0:f269e3021894 36
elessair 0:f269e3021894 37 uint32_t cfg2_muxsel = ADC_CFG2_MUXSEL_MASK;
elessair 0:f269e3021894 38 if (obj->adc & (1 << CHANNELS_A_SHIFT)) {
elessair 0:f269e3021894 39 cfg2_muxsel = 0;
elessair 0:f269e3021894 40 }
elessair 0:f269e3021894 41
elessair 0:f269e3021894 42 // bus clk
elessair 0:f269e3021894 43 uint32_t PCLK = bus_frequency();
elessair 0:f269e3021894 44 uint32_t clkdiv;
elessair 0:f269e3021894 45 for (clkdiv = 0; clkdiv < 4; clkdiv++) {
elessair 0:f269e3021894 46 if ((PCLK >> clkdiv) <= MAX_FADC)
elessair 0:f269e3021894 47 break;
elessair 0:f269e3021894 48 }
elessair 0:f269e3021894 49 if (clkdiv == 4) //Set max div
elessair 0:f269e3021894 50 clkdiv = 0x7;
elessair 0:f269e3021894 51
elessair 0:f269e3021894 52 ADC0->SC1[1] = ADC_SC1_ADCH(obj->adc & ~(1 << CHANNELS_A_SHIFT));
elessair 0:f269e3021894 53
elessair 0:f269e3021894 54 ADC0->CFG1 = ADC_CFG1_ADLPC_MASK // Low-Power Configuration
elessair 0:f269e3021894 55 | ADC_CFG1_ADIV(clkdiv & 0x3) // Clock Divide Select: (Input Clock)/8
elessair 0:f269e3021894 56 | ADC_CFG1_ADLSMP_MASK // Long Sample Time
elessair 0:f269e3021894 57 | ADC_CFG1_MODE(3) // (16)bits Resolution
elessair 0:f269e3021894 58 | ADC_CFG1_ADICLK(clkdiv >> 2); // Input Clock: (Bus Clock)/2
elessair 0:f269e3021894 59
elessair 0:f269e3021894 60 ADC0->CFG2 = cfg2_muxsel // ADxxb or ADxxa channels
elessair 0:f269e3021894 61 | ADC_CFG2_ADHSC_MASK // High-Speed Configuration
elessair 0:f269e3021894 62 | ADC_CFG2_ADLSTS(0); // Long Sample Time Select
elessair 0:f269e3021894 63
elessair 0:f269e3021894 64 ADC0->SC2 = ADC_SC2_REFSEL(0); // Default Voltage Reference
elessair 0:f269e3021894 65
elessair 0:f269e3021894 66 ADC0->SC3 = ADC_SC3_AVGE_MASK // Hardware Average Enable
elessair 0:f269e3021894 67 | ADC_SC3_AVGS(0); // 4 Samples Averaged
elessair 0:f269e3021894 68
elessair 0:f269e3021894 69 pinmap_pinout(pin, PinMap_ADC);
elessair 0:f269e3021894 70 }
elessair 0:f269e3021894 71
elessair 0:f269e3021894 72 uint16_t analogin_read_u16(analogin_t *obj) {
elessair 0:f269e3021894 73 // start conversion
elessair 0:f269e3021894 74 ADC0->SC1[0] = ADC_SC1_ADCH(obj->adc & ~(1 << CHANNELS_A_SHIFT));
elessair 0:f269e3021894 75
elessair 0:f269e3021894 76 // Wait Conversion Complete
elessair 0:f269e3021894 77 while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
elessair 0:f269e3021894 78
elessair 0:f269e3021894 79 // Return value
elessair 0:f269e3021894 80 return (uint16_t)ADC0->R[0];
elessair 0:f269e3021894 81 }
elessair 0:f269e3021894 82
elessair 0:f269e3021894 83 float analogin_read(analogin_t *obj) {
elessair 0:f269e3021894 84 uint16_t value = analogin_read_u16(obj);
elessair 0:f269e3021894 85 return (float)value * (1.0f / (float)0xFFFF);
elessair 0:f269e3021894 86 }
elessair 0:f269e3021894 87