Class similar to AnalogIn that uses burst mode to run continious background conversions so when the input is read, the last value can immediatly be returned.

Dependents:   KL25Z_FFT_Demo test_armmath KL25Z_FFT_Demo_tony KL25Z_FFT_Demo_tony ... more

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Show/hide line numbers FastAnalogIn_KLXX_K20D50M.cpp Source File

FastAnalogIn_KLXX_K20D50M.cpp

00001 #if defined(TARGET_KLXX) || defined(TARGET_K20D50M)
00002 
00003 #include "FastAnalogIn.h"
00004 #include "clk_freqs.h"
00005 
00006 #define MAX_FADC            6000000
00007 #define CHANNELS_A_SHIFT    5
00008 
00009 #ifdef TARGET_K20D50M
00010 static const PinMap PinMap_ADC[] = {
00011     {PTC2, ADC0_SE4b, 0},
00012     {PTD1, ADC0_SE5b, 0},
00013     {PTD5, ADC0_SE6b, 0},
00014     {PTD6, ADC0_SE7b, 0},
00015     {PTB0, ADC0_SE8,  0},
00016     {PTB1, ADC0_SE9,  0},
00017     {PTB2, ADC0_SE12, 0},
00018     {PTB3, ADC0_SE13, 0},
00019     {PTC0, ADC0_SE14, 0},
00020     {PTC1, ADC0_SE15, 0},
00021     {NC,   NC,        0}
00022 };
00023 #endif
00024 
00025 FastAnalogIn::FastAnalogIn(PinName pin, bool enabled)
00026 {
00027     ADCnumber = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
00028     if (ADCnumber == (ADCName)NC) {
00029         error("ADC pin mapping failed");
00030     }
00031 
00032     SIM->SCGC6 |= SIM_SCGC6_ADC0_MASK;
00033 
00034     uint32_t port = (uint32_t)pin >> PORT_SHIFT;
00035     SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
00036 
00037     uint32_t cfg2_muxsel = ADC_CFG2_MUXSEL_MASK;
00038     if (ADCnumber & (1 << CHANNELS_A_SHIFT)) {
00039         cfg2_muxsel = 0;
00040     }
00041     
00042     // bus clk
00043     uint32_t PCLK = bus_frequency();
00044     uint32_t clkdiv;
00045     for (clkdiv = 0; clkdiv < 4; clkdiv++) {
00046         if ((PCLK >> clkdiv) <= MAX_FADC)
00047             break;
00048     }
00049     if (clkdiv == 4)                    //Set max div
00050         clkdiv = 0x7;
00051 
00052     ADC0->SC1[1] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));
00053 
00054     ADC0->CFG1 = ADC_CFG1_ADIV(clkdiv & 0x3)    // Clock Divide Select: (Input Clock)/8
00055                | ADC_CFG1_MODE(3)               // (16)bits Resolution
00056                | ADC_CFG1_ADICLK(clkdiv >> 2);  // Input Clock: (Bus Clock)/2
00057 
00058     ADC0->CFG2 = cfg2_muxsel            // ADxxb or ADxxa channels
00059                | ADC_CFG2_ADACKEN_MASK  // Asynchronous Clock Output Enable
00060                | ADC_CFG2_ADHSC_MASK;   // High-Speed Configuration
00061 
00062     ADC0->SC2 = ADC_SC2_REFSEL(0);      // Default Voltage Reference
00063 
00064     pinmap_pinout(pin, PinMap_ADC);
00065 
00066     //Enable channel
00067     running = false;
00068     enable(enabled);
00069 }
00070 
00071 void FastAnalogIn::enable(bool enabled)
00072 {
00073     //If currently not running
00074     if (!running) {
00075         if (enabled) {
00076             //Enable the ADC channel
00077             ADC0->SC3 |= ADC_SC3_ADCO_MASK;       // Enable continuous conversion
00078             ADC0->SC1[0] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));  //Start conversion
00079             running = true;
00080         } else
00081             disable();
00082     }
00083 }
00084  
00085 void FastAnalogIn::disable( void )
00086 {
00087     //If currently running
00088     if (running) {
00089         ADC0->SC3 &= ~ADC_SC3_ADCO_MASK;      // Disable continuous conversion
00090     }
00091     running = false;
00092 }
00093 
00094 uint16_t FastAnalogIn::read_u16()
00095 {
00096     if (!running)
00097     {
00098         // start conversion
00099         ADC0->SC1[0] = ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT));
00100         // Wait Conversion Complete
00101         while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
00102     }
00103     if(running && ((ADC0->SC1[0]&ADC_SC1_ADCH_MASK) != (ADC_SC1_ADCH(ADCnumber & ~(1 << CHANNELS_A_SHIFT)))))
00104     {
00105         running = false;
00106         enable();
00107         while ((ADC0->SC1[0] & ADC_SC1_COCO_MASK) != ADC_SC1_COCO_MASK);
00108     }
00109     // Return value
00110     return (uint16_t)ADC0->R[0];
00111 }
00112 
00113 #endif //defined TARGET_KLXX
00114