cebri alyac / FastPWM

yes

Device/FastPWM_KLXX_K20D50M.cpp@0:c60399891edd, 2022-05-08 (annotated)

Committer:
braichi13
Date:
Sun May 08 14:39:57 2022 +0000
Revision:
0:c60399891edd
Yes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
braichi13 0:c60399891edd 1 #if defined(TARGET_KLXX) || defined(TARGET_K20D50M)
braichi13 0:c60399891edd 2
braichi13 0:c60399891edd 3 #include "FastPWM.h"
braichi13 0:c60399891edd 4
braichi13 0:c60399891edd 5 void FastPWM::initFastPWM( void ) {
braichi13 0:c60399891edd 6 bits = 16;
braichi13 0:c60399891edd 7 }
braichi13 0:c60399891edd 8
braichi13 0:c60399891edd 9 void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
braichi13 0:c60399891edd 10 *(_pwm.CnV) = ticks;
braichi13 0:c60399891edd 11 }
braichi13 0:c60399891edd 12
braichi13 0:c60399891edd 13 void FastPWM::period_ticks( uint32_t ticks ) {
braichi13 0:c60399891edd 14 *(_pwm.MOD) = ticks - 1;
braichi13 0:c60399891edd 15 }
braichi13 0:c60399891edd 16
braichi13 0:c60399891edd 17 uint32_t FastPWM::getPeriod( void ) {
braichi13 0:c60399891edd 18 return *(_pwm.MOD) + 1;
braichi13 0:c60399891edd 19 }
braichi13 0:c60399891edd 20
braichi13 0:c60399891edd 21 uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
braichi13 0:c60399891edd 22
braichi13 0:c60399891edd 23 //Yes this is ugly, yes I should feel bad about it
braichi13 0:c60399891edd 24 volatile uint32_t *TPM_SC = _pwm.MOD - 2;
braichi13 0:c60399891edd 25
braichi13 0:c60399891edd 26 const char prescalers[] = {1, 2, 4, 8, 16, 32, 64, 128};
braichi13 0:c60399891edd 27
braichi13 0:c60399891edd 28 //If prescaler is 0, return current one
braichi13 0:c60399891edd 29 if (reqScale == 0)
braichi13 0:c60399891edd 30 return (prescalers[(*TPM_SC) & 0x07]);
braichi13 0:c60399891edd 31
braichi13 0:c60399891edd 32 uint32_t retval = 0;
braichi13 0:c60399891edd 33 char bin;
braichi13 0:c60399891edd 34
braichi13 0:c60399891edd 35 for (bin = 0; bin<8; bin++) {
braichi13 0:c60399891edd 36 retval = prescalers[bin];
braichi13 0:c60399891edd 37 if (retval >= reqScale)
braichi13 0:c60399891edd 38 break;
braichi13 0:c60399891edd 39 }
braichi13 0:c60399891edd 40 if (bin == 8)
braichi13 0:c60399891edd 41 bin = 7;
braichi13 0:c60399891edd 42
braichi13 0:c60399891edd 43 //Clear lower 5 bits, write new value:
braichi13 0:c60399891edd 44 char clockbits = *TPM_SC & (3<<3);
braichi13 0:c60399891edd 45
braichi13 0:c60399891edd 46 //For some reason clearing them takes some effort
braichi13 0:c60399891edd 47 while ((*TPM_SC & 0x1F) != 0)
braichi13 0:c60399891edd 48 *TPM_SC &= ~0x1F;
braichi13 0:c60399891edd 49
braichi13 0:c60399891edd 50
braichi13 0:c60399891edd 51 *TPM_SC = bin + clockbits;
braichi13 0:c60399891edd 52
braichi13 0:c60399891edd 53 return retval;
braichi13 0:c60399891edd 54 }
braichi13 0:c60399891edd 55 #endif