FastAnalogIn_KLXX.cpp

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