Kang mingyo
FASTPWM
Device/FastPWM_STM_TIM.cpp@22:db9c0cf445e2, 2015-04-16 (annotated)
- Committer:
- Sissors
- Date:
- Thu Apr 16 19:23:53 2015 +0000
- Revision:
- 22:db9c0cf445e2
- Parent:
- 17:8378bc456f0d
- Child:
- 24:1f451660d8c0
Fixed a bug for STM targets. The mbed library did not enable syncing of the period register, resulting in sometimes a smaller period being set than the current timer value -> it would first need to overflow before it worked properly. Which takes long o...
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| Sissors | 13:cdefd9d75b64 | 1 | //This should (hopefully) work on all STM targets which use TIM timers for PWM |
| Sissors | 13:cdefd9d75b64 | 2 | |
| Sissors | 13:cdefd9d75b64 | 3 | #ifdef TARGET_STM |
| Sissors | 13:cdefd9d75b64 | 4 | |
| Sissors | 13:cdefd9d75b64 | 5 | #include "FastPWM.h" |
| Sissors | 13:cdefd9d75b64 | 6 | |
| jocis | 17:8378bc456f0d | 7 | #if defined TARGET_NUCLEO_F103RB |
| jocis | 17:8378bc456f0d | 8 | typedef __IO uint16_t* CHANNEL_P_T; |
| jocis | 17:8378bc456f0d | 9 | #else |
| jocis | 17:8378bc456f0d | 10 | typedef __IO uint32_t* CHANNEL_P_T; |
| jocis | 17:8378bc456f0d | 11 | #endif |
| jocis | 17:8378bc456f0d | 12 | |
| jocis | 17:8378bc456f0d | 13 | #define PWM_CHANNEL (**(CHANNEL_P_T*)fast_obj) |
| Sissors | 13:cdefd9d75b64 | 14 | #define PWM_TIMER ((TIM_TypeDef*)_pwm.pwm) |
| Sissors | 13:cdefd9d75b64 | 15 | |
| jocis | 17:8378bc456f0d | 16 | extern CHANNEL_P_T getChannel(TIM_TypeDef* pwm, PinName pin); |
| Sissors | 13:cdefd9d75b64 | 17 | |
| Sissors | 13:cdefd9d75b64 | 18 | void FastPWM::initFastPWM( void ) { |
| jocis | 17:8378bc456f0d | 19 | fast_obj = new (CHANNEL_P_T); |
| jocis | 17:8378bc456f0d | 20 | *(CHANNEL_P_T*)fast_obj = getChannel(PWM_TIMER, _pwm.pin); |
| jocis | 17:8378bc456f0d | 21 | |
| Sissors | 22:db9c0cf445e2 | 22 | //Enable PWM period syncing for glitch free result |
| Sissors | 22:db9c0cf445e2 | 23 | PWM_TIMER->CR1 |= TIM_CR1_ARPE; |
| Sissors | 22:db9c0cf445e2 | 24 | |
| Sissors | 13:cdefd9d75b64 | 25 | bits = 16; |
| Sissors | 13:cdefd9d75b64 | 26 | } |
| Sissors | 13:cdefd9d75b64 | 27 | |
| Sissors | 13:cdefd9d75b64 | 28 | void FastPWM::pulsewidth_ticks( uint32_t ticks ) { |
| Sissors | 13:cdefd9d75b64 | 29 | PWM_CHANNEL = ticks; |
| Sissors | 13:cdefd9d75b64 | 30 | } |
| Sissors | 13:cdefd9d75b64 | 31 | |
| Sissors | 13:cdefd9d75b64 | 32 | void FastPWM::period_ticks( uint32_t ticks ) { |
| Sissors | 13:cdefd9d75b64 | 33 | PWM_TIMER->ARR = ticks - 1; |
| Sissors | 13:cdefd9d75b64 | 34 | } |
| Sissors | 13:cdefd9d75b64 | 35 | |
| Sissors | 13:cdefd9d75b64 | 36 | uint32_t FastPWM::getPeriod( void ) { |
| Sissors | 13:cdefd9d75b64 | 37 | return PWM_TIMER->ARR + 1; |
| Sissors | 13:cdefd9d75b64 | 38 | } |
| Sissors | 13:cdefd9d75b64 | 39 | |
| Sissors | 13:cdefd9d75b64 | 40 | uint32_t FastPWM::setPrescaler(uint32_t reqScale) { |
| Sissors | 13:cdefd9d75b64 | 41 | if (reqScale == 0) |
| Sissors | 13:cdefd9d75b64 | 42 | //Return prescaler |
| Sissors | 13:cdefd9d75b64 | 43 | return PWM_TIMER->PSC + 1; |
| Sissors | 13:cdefd9d75b64 | 44 | if (reqScale > (uint32_t)(1<<16)) |
| Sissors | 13:cdefd9d75b64 | 45 | reqScale = 1<<16; |
| Sissors | 13:cdefd9d75b64 | 46 | //Else set prescaler, we have to substract one from reqScale since a 0 in PCVAL is prescaler of 1 |
| Sissors | 13:cdefd9d75b64 | 47 | PWM_TIMER->PSC = reqScale - 1; |
| Sissors | 13:cdefd9d75b64 | 48 | |
| Sissors | 13:cdefd9d75b64 | 49 | return reqScale; |
| Sissors | 13:cdefd9d75b64 | 50 | } |
| Sissors | 13:cdefd9d75b64 | 51 | |
| Sissors | 13:cdefd9d75b64 | 52 | #endif |