BX-adc.cpp

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