Alp Sayin / FastPWM

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Fork of FastPWM by Erik -

Device/FastPWM_KL25Z.cpp@4:a7b9f778c4b4, 2013-08-13 (annotated)

Committer:
Sissors
Date:
Tue Aug 13 16:54:06 2013 +0000
Revision:
4:a7b9f778c4b4
v2.0

; Added KL25Z/LPC11u24 support

; Added prescalers

; Direct tick changes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 4:a7b9f778c4b4 1 #ifdef TARGET_KL25Z
Sissors 4:a7b9f778c4b4 2
Sissors 4:a7b9f778c4b4 3 #include "FastPWM.h"
Sissors 4:a7b9f778c4b4 4
Sissors 4:a7b9f778c4b4 5 volatile uint32_t *TPM_SC;
Sissors 4:a7b9f778c4b4 6
Sissors 4:a7b9f778c4b4 7 void FastPWM::initFastPWM( void ) {
Sissors 4:a7b9f778c4b4 8 bits = 16;
Sissors 4:a7b9f778c4b4 9
Sissors 4:a7b9f778c4b4 10 //Yes this is ugly, yes I should feel bad about it
Sissors 4:a7b9f778c4b4 11 TPM_SC = _pwm.MOD - 2;
Sissors 4:a7b9f778c4b4 12 }
Sissors 4:a7b9f778c4b4 13
Sissors 4:a7b9f778c4b4 14 void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
Sissors 4:a7b9f778c4b4 15 *(_pwm.CnV) = ticks;
Sissors 4:a7b9f778c4b4 16 *_pwm.CNT = 0; //Not yet sure why this is needed!
Sissors 4:a7b9f778c4b4 17 }
Sissors 4:a7b9f778c4b4 18
Sissors 4:a7b9f778c4b4 19 void FastPWM::period_ticks( uint32_t ticks ) {
Sissors 4:a7b9f778c4b4 20 *(_pwm.MOD) = ticks;
Sissors 4:a7b9f778c4b4 21 *_pwm.CNT = 0;
Sissors 4:a7b9f778c4b4 22 }
Sissors 4:a7b9f778c4b4 23
Sissors 4:a7b9f778c4b4 24 uint32_t FastPWM::getPeriod( void ) {
Sissors 4:a7b9f778c4b4 25 return *(_pwm.MOD);
Sissors 4:a7b9f778c4b4 26 }
Sissors 4:a7b9f778c4b4 27
Sissors 4:a7b9f778c4b4 28 uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
Sissors 4:a7b9f778c4b4 29 const char prescalers[] = {1, 2, 4, 8, 16, 32, 64, 128};
Sissors 4:a7b9f778c4b4 30
Sissors 4:a7b9f778c4b4 31 //If prescaler is 0, return current one
Sissors 4:a7b9f778c4b4 32 if (reqScale == 0)
Sissors 4:a7b9f778c4b4 33 return (prescalers[(*TPM_SC) & 0x07]);
Sissors 4:a7b9f778c4b4 34
Sissors 4:a7b9f778c4b4 35 uint32_t retval = 0;
Sissors 4:a7b9f778c4b4 36 char bin;
Sissors 4:a7b9f778c4b4 37
Sissors 4:a7b9f778c4b4 38 for (bin = 0; bin<8; bin++) {
Sissors 4:a7b9f778c4b4 39 retval = prescalers[bin];
Sissors 4:a7b9f778c4b4 40 if (retval >= reqScale)
Sissors 4:a7b9f778c4b4 41 break;
Sissors 4:a7b9f778c4b4 42 }
Sissors 4:a7b9f778c4b4 43
Sissors 4:a7b9f778c4b4 44 //Clear lower 5 bits, write new value:
Sissors 4:a7b9f778c4b4 45 char clockbits = *TPM_SC & (3<<3);
Sissors 4:a7b9f778c4b4 46
Sissors 4:a7b9f778c4b4 47 //For some reason clearing them takes some effort
Sissors 4:a7b9f778c4b4 48 while ((*TPM_SC & 0x1F) != 0)
Sissors 4:a7b9f778c4b4 49 *TPM_SC &= ~0x1F;
Sissors 4:a7b9f778c4b4 50
Sissors 4:a7b9f778c4b4 51
Sissors 4:a7b9f778c4b4 52 *TPM_SC |= bin + clockbits;
Sissors 4:a7b9f778c4b4 53
Sissors 4:a7b9f778c4b4 54 return retval;
Sissors 4:a7b9f778c4b4 55 }
Sissors 4:a7b9f778c4b4 56 #endif