FastPWM_KSDK.cpp

00001 #if defined(TARGET_KPSDK_MCUS)
00002 
00003 #include "FastPWM.h"
00004 #include "fsl_clock_manager.h"
00005 
00006 
00007 #define PWM_CNV              (*(((fastpwm_struct*)fast_obj)->CnV))  
00008 #define PWM_MOD              (*(((fastpwm_struct*)fast_obj)->MOD))  
00009 #define PWM_SC               (*(((fastpwm_struct*)fast_obj)->SC))  
00010 
00011 typedef struct  {
00012     __IO uint32_t *CnV;
00013     __IO uint32_t *MOD;
00014     __IO uint32_t *SC;
00015 } fastpwm_struct;
00016 
00017 static uint32_t pwm_prescaler;
00018 
00019 void FastPWM::initFastPWM( void ) {
00020     fast_obj = new fastpwm_struct;
00021     bits = 16;
00022     
00023     uint32_t pwm_base_clock;
00024     CLOCK_SYS_GetFreq(kBusClock, &pwm_base_clock);
00025     pwm_prescaler = SystemCoreClock / pwm_base_clock;
00026 
00027     uint32_t ftms[] = FTM_BASE_ADDRS;
00028     unsigned int ch_n = (_pwm.pwm_name & 0xFF);
00029     FTM_Type *ftm = (FTM_Type *)ftms[_pwm.pwm_name >> TPM_SHIFT];
00030     
00031     ((fastpwm_struct*)fast_obj)->CnV = &ftm->CONTROLS[ch_n].CnV;
00032     ((fastpwm_struct*)fast_obj)->MOD = &ftm->MOD;
00033     ((fastpwm_struct*)fast_obj)->SC = &ftm->SC;
00034 }
00035 
00036 void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
00037     PWM_CNV = ticks;
00038 }
00039 
00040 void FastPWM::period_ticks( uint32_t ticks ) {
00041     PWM_MOD = ticks - 1;
00042 }
00043 
00044 uint32_t FastPWM::getPeriod( void ) {
00045     return PWM_MOD + 1;
00046 }
00047 
00048 uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
00049  
00050     uint32_t prescalers[] = {1, 2, 4, 8, 16, 32, 64, 128};
00051     
00052     for (int i = 0; i<8; i++)
00053          prescalers[i] = prescalers[i] * pwm_prescaler;
00054     
00055     //If prescaler is 0, return current one
00056     if (reqScale == 0)
00057         return (prescalers[(PWM_SC) & 0x07]);
00058     
00059     uint32_t retval = 0;
00060     char bin;
00061     
00062     for (bin = 0; bin<8; bin++) {
00063         retval = prescalers[bin];
00064         if (retval >= reqScale)
00065             break;
00066     }
00067     if (bin == 8)
00068         bin = 7;
00069     
00070     //Clear lower 5 bits, write new value:
00071     char clockbits = PWM_SC & (3<<3);
00072     
00073     //For some reason clearing them takes some effort
00074     while ((PWM_SC & 0x1F) != 0)
00075         PWM_SC &= ~0x1F;
00076         
00077     
00078     PWM_SC = bin + clockbits;
00079     
00080     return retval;   
00081 }
00082 #endif