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Fork of FastPWM by
Device/FastPWM_LPC11U24.cpp
- Committer:
- Sissors
- Date:
- 2014-07-20
- Revision:
- 12:4600daab8a83
- Parent:
- 10:36362e9067b0
File content as of revision 12:4600daab8a83:
#ifdef TARGET_LPC11U24
#include "FastPWM.h"
#define PWM_MR (*(((fastpwm_struct*)fast_obj)->MR))
#define PWM_TIMER (((fastpwm_struct*)fast_obj)->timer)
typedef struct {
__IO uint32_t *MR;
LPC_CTxxBx_Type *timer;
} fastpwm_struct;
typedef struct {
uint8_t timer;
uint8_t mr;
} timer_mr;
static timer_mr pwm_timer_map[11] = {
{0, 0}, {0, 1}, {0, 2},
{1, 0}, {1, 1},
{2, 0}, {2, 1}, {2, 2},
{3, 0}, {3, 1}, {3, 2},
};
static LPC_CTxxBx_Type *Timers[4] = {
LPC_CT16B0, LPC_CT16B1,
LPC_CT32B0, LPC_CT32B1
};
void FastPWM::initFastPWM( void ) {
fast_obj = new fastpwm_struct;
timer_mr tid = pwm_timer_map[_pwm.pwm];
PWM_TIMER = Timers[tid.timer];
(((fastpwm_struct*)fast_obj)->MR) = &PWM_TIMER->MR[tid.mr];
if (tid.timer < 2)
//16-bit timer
bits = 16;
else
//32-bit timer
bits = 32;
}
void FastPWM::pulsewidth_ticks( uint32_t ticks ) {
if (ticks)
PWM_MR = PWM_TIMER->MR3 - ticks; //They inverted PWM on the 11u24
else
PWM_MR = 0xFFFFFFFF; //If MR3 = ticks 1 clock cycle wide errors appear, this prevents that (unless MR3 = max).
}
void FastPWM::period_ticks( uint32_t ticks ) {
PWM_TIMER->TCR = 0x02;
PWM_TIMER->MR3 = ticks;
PWM_TIMER->TCR = 0x01;
}
uint32_t FastPWM::getPeriod( void ) {
return PWM_TIMER->MR3;
}
uint32_t FastPWM::setPrescaler(uint32_t reqScale) {
//If 32-bit, disable auto-scaling, return 1
if (bits == 32) {
dynamicPrescaler = false;
return 1;
}
//Else 16-bit timer:
if (reqScale == 0)
//Return prescaler
return PWM_TIMER->PR + 1;
if (reqScale > (uint32_t)(1<<16))
reqScale = 1<<16;
//Else set prescaler, we have to substract one from reqScale since a 0 in PCVAL is prescaler of 1
PWM_TIMER->PR = reqScale - 1;
return reqScale;
}
#endif
