Andrey Sverdlichenko / FastPWM

FastPWM clone

Device/FastPWM_KSDK.cpp@31:10e2e171f430, 2016-09-06 (annotated)

Committer:
Sissors
Date:
Tue Sep 06 20:17:21 2016 +0000
Revision:
31:10e2e171f430
Parent:
14:b30038fbba51
Child:
33:2ca2e47f9650
Temporary fix for K64F with new mbed lib:

; 1. KSDK funtions changed (fixed)

; 2. Mbed uses a completely different mode for the PWM, which screws up my code. (Temp fix, don't call write directly after setting a new period, but wait 1 pwm period)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 14:b30038fbba51 1 #if defined(TARGET_KPSDK_MCUS)
Sissors 14:b30038fbba51 2
Sissors 14:b30038fbba51 3 #include "FastPWM.h"
Sissors 31:10e2e171f430 4 #include "fsl_ftm.h"
Sissors 14:b30038fbba51 5
Sissors 14:b30038fbba51 6
Sissors 14:b30038fbba51 7 #define PWM_CNV (*(((fastpwm_struct*)fast_obj)->CnV))
Sissors 14:b30038fbba51 8 #define PWM_MOD (*(((fastpwm_struct*)fast_obj)->MOD))
Sissors 14:b30038fbba51 9 #define PWM_SC (*(((fastpwm_struct*)fast_obj)->SC))
Sissors 14:b30038fbba51 10
Sissors 14:b30038fbba51 11 typedef struct {
Sissors 14:b30038fbba51 12 __IO uint32_t *CnV;
Sissors 14:b30038fbba51 13 __IO uint32_t *MOD;
Sissors 14:b30038fbba51 14 __IO uint32_t *SC;
Sissors 14:b30038fbba51 15 } fastpwm_struct;
Sissors 14:b30038fbba51 16
Sissors 14:b30038fbba51 17 static uint32_t pwm_prescaler;
Sissors 31:10e2e171f430 18 static FTM_Type *const ftm_addrs[] = FTM_BASE_PTRS;
Sissors 14:b30038fbba51 19
Sissors 14:b30038fbba51 20 void FastPWM::initFastPWM( void ) {
Sissors 14:b30038fbba51 21 fast_obj = new fastpwm_struct;
Sissors 14:b30038fbba51 22 bits = 16;
Sissors 31:10e2e171f430 23
Sissors 31:10e2e171f430 24 pwm_prescaler = SystemCoreClock / CLOCK_GetFreq(kCLOCK_BusClk);;
Sissors 14:b30038fbba51 25
Sissors 31:10e2e171f430 26 unsigned int ch_n = (_pwm.pwm_name & 0xF);
Sissors 31:10e2e171f430 27 FTM_Type *ftm = ftm_addrs[_pwm.pwm_name >> TPM_SHIFT];
Sissors 14:b30038fbba51 28
Sissors 14:b30038fbba51 29 ((fastpwm_struct*)fast_obj)->CnV = &ftm->CONTROLS[ch_n].CnV;
Sissors 14:b30038fbba51 30 ((fastpwm_struct*)fast_obj)->MOD = &ftm->MOD;
Sissors 14:b30038fbba51 31 ((fastpwm_struct*)fast_obj)->SC = &ftm->SC;
Sissors 14:b30038fbba51 32 }
Sissors 14:b30038fbba51 33
Sissors 14:b30038fbba51 34 void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
Sissors 14:b30038fbba51 35 PWM_CNV = ticks;
Sissors 31:10e2e171f430 36
Sissors 31:10e2e171f430 37 //Temporary work around until I figure out which settings mbed screwed up in this update
Sissors 31:10e2e171f430 38 FTM_Type *ftm = ftm_addrs[_pwm.pwm_name >> TPM_SHIFT];
Sissors 31:10e2e171f430 39 FTM_SetSoftwareTrigger(ftm, true);
Sissors 14:b30038fbba51 40 }
Sissors 14:b30038fbba51 41
Sissors 14:b30038fbba51 42 void FastPWM::period_ticks( uint32_t ticks ) {
Sissors 14:b30038fbba51 43 PWM_MOD = ticks - 1;
Sissors 14:b30038fbba51 44 }
Sissors 14:b30038fbba51 45
Sissors 14:b30038fbba51 46 uint32_t FastPWM::getPeriod( void ) {
Sissors 14:b30038fbba51 47 return PWM_MOD + 1;
Sissors 14:b30038fbba51 48 }
Sissors 14:b30038fbba51 49
Sissors 14:b30038fbba51 50 uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
Sissors 14:b30038fbba51 51
Sissors 14:b30038fbba51 52 uint32_t prescalers[] = {1, 2, 4, 8, 16, 32, 64, 128};
Sissors 14:b30038fbba51 53
Sissors 14:b30038fbba51 54 for (int i = 0; i<8; i++)
Sissors 14:b30038fbba51 55 prescalers[i] = prescalers[i] * pwm_prescaler;
Sissors 14:b30038fbba51 56
Sissors 14:b30038fbba51 57 //If prescaler is 0, return current one
Sissors 14:b30038fbba51 58 if (reqScale == 0)
Sissors 14:b30038fbba51 59 return (prescalers[(PWM_SC) & 0x07]);
Sissors 14:b30038fbba51 60
Sissors 14:b30038fbba51 61 uint32_t retval = 0;
Sissors 14:b30038fbba51 62 char bin;
Sissors 14:b30038fbba51 63
Sissors 14:b30038fbba51 64 for (bin = 0; bin<8; bin++) {
Sissors 14:b30038fbba51 65 retval = prescalers[bin];
Sissors 14:b30038fbba51 66 if (retval >= reqScale)
Sissors 14:b30038fbba51 67 break;
Sissors 14:b30038fbba51 68 }
Sissors 14:b30038fbba51 69 if (bin == 8)
Sissors 14:b30038fbba51 70 bin = 7;
Sissors 14:b30038fbba51 71
Sissors 14:b30038fbba51 72 //Clear lower 5 bits, write new value:
Sissors 14:b30038fbba51 73 char clockbits = PWM_SC & (3<<3);
Sissors 14:b30038fbba51 74
Sissors 14:b30038fbba51 75 //For some reason clearing them takes some effort
Sissors 14:b30038fbba51 76 while ((PWM_SC & 0x1F) != 0)
Sissors 14:b30038fbba51 77 PWM_SC &= ~0x1F;
Sissors 14:b30038fbba51 78
Sissors 14:b30038fbba51 79
Sissors 14:b30038fbba51 80 PWM_SC = bin + clockbits;
Sissors 14:b30038fbba51 81
Sissors 14:b30038fbba51 82 return retval;
Sissors 14:b30038fbba51 83 }
Sissors 14:b30038fbba51 84 #endif