Clark Lin / Mbed 2 deprecated BX-car_s

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Dependencies:   mbed-rtos mbed

Fork of BX-car_s by Tony Lin

bx-adc.cpp@23:d6d4e8adf7fe, 2014-07-02 (annotated)

Committer:
physicsgood
Date:
Wed Jul 02 13:33:49 2014 +0000
Revision:
23:d6d4e8adf7fe
Parent:
1:82bc25a7b68b 
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Who changed what in which revision?

UserRevisionLine numberNew contents of line
backman 1:82bc25a7b68b 1 #include "bx-adc.h"
backman 1:82bc25a7b68b 2 #include "clk_freqs.h"
backman 1:82bc25a7b68b 3
backman 1:82bc25a7b68b 4 #define MAX_FADC 6000000
backman 1:82bc25a7b68b 5 #define CHANNELS_A_SHIFT 5
backman 1:82bc25a7b68b 6
backman 1:82bc25a7b68b 7 FastAnalogIn::FastAnalogIn(PinName pin, bool enabled)
backman 1:82bc25a7b68b 8 {
backman 1:82bc25a7b68b 9 ADCnumber = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
backman 1:82bc25a7b68b 10 if (ADCnumber == (ADCName)NC) {
backman 1:82bc25a7b68b 11 error("ADC pin mapping failed");
backman 1:82bc25a7b68b 12 }
backman 1:82bc25a7b68b 13
backman 1:82bc25a7b68b 14 SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
backman 1:82bc25a7b68b 15 //-----------------------------------------------------
backman 1:82bc25a7b68b 16 uint32_t port = (uint32_t)pin >> PORT_SHIFT;
backman 1:82bc25a7b68b 17 SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
backman 1:82bc25a7b68b 18
backman 1:82bc25a7b68b 19 uint32_t cfg2_muxsel = ADC_CFG2_MUXSEL_MASK;
backman 1:82bc25a7b68b 20 if (ADCnumber & (1 << CHANNELS_A_SHIFT)) {
backman 1:82bc25a7b68b 21 cfg2_muxsel = 0;
backman 1:82bc25a7b68b 22 }
backman 1:82bc25a7b68b 23 //------------------------------------------------------
backman 1:82bc25a7b68b 24 // bus clk
backman 1:82bc25a7b68b 25 uint32_t PCLK = bus_frequency();
backman 1:82bc25a7b68b 26 uint32_t clkdiv;
backman 1:82bc25a7b68b 27 for (clkdiv = 0; clkdiv < 4; clkdiv++) {
backman 1:82bc25a7b68b 28 if ((PCLK >> clkdiv) <= MAX_FADC)
backman 1:82bc25a7b68b 29 break;
backman 1:82bc25a7b68b 30 }
backman 1:82bc25a7b68b 31 if (clkdiv == 4) //Set max div
backman 1:82bc25a7b68b 32 clkdiv = 0x7;
backman 1:82bc25a7b68b 33
backman 1:82bc25a7b68b 34 ADC0->SC1[1] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));
backman 1:82bc25a7b68b 35
backman 1:82bc25a7b68b 36 ADC0->CFG1 = ADC_CFG1_ADIV(clkdiv & 0x3) // Clock Divide Select: (Input Clock)/8
backman 1:82bc25a7b68b 37 | ADC_CFG1_MODE(3) // (16)bits Resolution
backman 1:82bc25a7b68b 38 | ADC_CFG1_ADICLK(clkdiv >> 2); // Input Clock: (Bus Clock)/2
backman 1:82bc25a7b68b 39
backman 1:82bc25a7b68b 40 ADC0->CFG2 = cfg2_muxsel // ADxxb or ADxxa channels
backman 1:82bc25a7b68b 41 | ADC_CFG2_ADACKEN_MASK // Asynchronous Clock Output Enable
backman 1:82bc25a7b68b 42 | ADC_CFG2_ADHSC_MASK; // High-Speed Configuration
backman 1:82bc25a7b68b 43
backman 1:82bc25a7b68b 44 ADC0->SC2 = ADC_SC2_REFSEL(0); // Default Voltage Reference
backman 1:82bc25a7b68b 45
backman 1:82bc25a7b68b 46 pinmap_pinout(pin, PinMap_ADC);
backman 1:82bc25a7b68b 47
backman 1:82bc25a7b68b 48 //Enable channel
backman 1:82bc25a7b68b 49 running = false;
backman 1:82bc25a7b68b 50 enable(enabled);
backman 1:82bc25a7b68b 51 }
backman 1:82bc25a7b68b 52
backman 1:82bc25a7b68b 53 void FastAnalogIn::enable(bool enabled)
backman 1:82bc25a7b68b 54 {
backman 1:82bc25a7b68b 55 //If currently not running
backman 1:82bc25a7b68b 56 if (!running) {
backman 1:82bc25a7b68b 57 if (enabled) {
backman 1:82bc25a7b68b 58 //Enable the ADC channel
backman 1:82bc25a7b68b 59 ADC0->SC3 |= ADC_SC3_ADCO_MASK; // Enable continuous conversion
backman 1:82bc25a7b68b 60 ADC0->SC1[0] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT)); //Start conversion
backman 1:82bc25a7b68b 61 running = true;
backman 1:82bc25a7b68b 62 } else
backman 1:82bc25a7b68b 63 disable();
backman 1:82bc25a7b68b 64 }
backman 1:82bc25a7b68b 65 }
backman 1:82bc25a7b68b 66
backman 1:82bc25a7b68b 67 void FastAnalogIn::disable( void )
backman 1:82bc25a7b68b 68 {
backman 1:82bc25a7b68b 69 //If currently running
backman 1:82bc25a7b68b 70 if (running) {
backman 1:82bc25a7b68b 71 ADC0->SC3 &= ~ADC_SC3_ADCO_MASK; // Disable continuous conversion
backman 1:82bc25a7b68b 72 }
backman 1:82bc25a7b68b 73 running = false;
backman 1:82bc25a7b68b 74 }
backman 1:82bc25a7b68b 75
backman 1:82bc25a7b68b 76 uint16_t FastAnalogIn::read_u16()
backman 1:82bc25a7b68b 77 {
backman 1:82bc25a7b68b 78 if (!running)
backman 1:82bc25a7b68b 79 {
backman 1:82bc25a7b68b 80 // start conversion
backman 1:82bc25a7b68b 81 ADC0->SC1[0] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));
backman 1:82bc25a7b68b 82 // Wait Conversion Complete
backman 1:82bc25a7b68b 83 while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
backman 1:82bc25a7b68b 84 }
backman 1:82bc25a7b68b 85 if(running && ((ADC0->SC1[0]&ADC_SC1_ADCH_MASK) != (ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT)))))
backman 1:82bc25a7b68b 86 {
backman 1:82bc25a7b68b 87 running = false;
backman 1:82bc25a7b68b 88 enable();
backman 1:82bc25a7b68b 89 while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
backman 1:82bc25a7b68b 90 }
backman 1:82bc25a7b68b 91 // Return value
backman 1:82bc25a7b68b 92 return (uint16_t)ADC0->R[0];
backman 1:82bc25a7b68b 93 }
backman 1:82bc25a7b68b 94