mirror of https://github.com/ARMmbed/mbed-os.git
92 lines
2.9 KiB
C
92 lines
2.9 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "mbed_assert.h"
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#include "analogin_api.h"
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#include "cmsis.h"
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#include "pinmap.h"
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#include "clk_freqs.h"
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#include "PeripheralPins.h"
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#define MAX_FADC 6000000
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#define CHANNELS_A_SHIFT 5
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void analogin_init(analogin_t *obj, PinName pin) {
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obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
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MBED_ASSERT(obj->adc != (ADCName)NC);
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SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
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uint32_t port = (uint32_t)pin >> PORT_SHIFT;
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SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
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uint32_t cfg2_muxsel = ADC_CFG2_MUXSEL_MASK;
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if (obj->adc & (1 << CHANNELS_A_SHIFT)) {
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cfg2_muxsel = 0;
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}
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// bus clk
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uint32_t PCLK = bus_frequency();
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uint32_t clkdiv;
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for (clkdiv = 0; clkdiv < 4; clkdiv++) {
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if ((PCLK >> clkdiv) <= MAX_FADC)
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break;
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}
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if (clkdiv == 4) //Set max div
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clkdiv = 0x7;
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ADC0->SC1[1] = ADC_SC1_ADCH(obj->adc & ~(1 << CHANNELS_A_SHIFT));
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ADC0->CFG1 = ADC_CFG1_ADLPC_MASK // Low-Power Configuration
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| ADC_CFG1_ADIV(clkdiv & 0x3) // Clock Divide Select: (Input Clock)/8
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| ADC_CFG1_ADLSMP_MASK // Long Sample Time
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| ADC_CFG1_MODE(3) // (16)bits Resolution
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| ADC_CFG1_ADICLK(clkdiv >> 2); // Input Clock: (Bus Clock)/2
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ADC0->CFG2 = cfg2_muxsel // ADxxb or ADxxa channels
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| ADC_CFG2_ADHSC_MASK // High-Speed Configuration
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| ADC_CFG2_ADLSTS(0); // Long Sample Time Select
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ADC0->SC2 = ADC_SC2_REFSEL(0); // Default Voltage Reference
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ADC0->SC3 = ADC_SC3_AVGE_MASK // Hardware Average Enable
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| ADC_SC3_AVGS(0); // 4 Samples Averaged
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pinmap_pinout(pin, PinMap_ADC);
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}
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uint16_t analogin_read_u16(analogin_t *obj) {
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// start conversion
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ADC0->SC1[0] = ADC_SC1_ADCH(obj->adc & ~(1 << CHANNELS_A_SHIFT));
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// Wait Conversion Complete
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while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
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// Return value
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return (uint16_t)ADC0->R[0];
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}
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float analogin_read(analogin_t *obj) {
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uint16_t value = analogin_read_u16(obj);
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return (float)value * (1.0f / (float)0xFFFF);
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}
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const PinMap *analogin_pinmap()
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{
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return PinMap_ADC;
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}
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