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SiLabs Pearl: PWM output functionality 

Any channel can be used. It is possible to have 4 pwm outputs
active at a same time, if PinMap_PWM configuration is done properly.

Future improvement proposal: dynamic channel selection!
pull/1501/head
jhokajar 2015-10-20 15:12:42 +03:00 committed by Steven Cooreman
parent 973141e2e7
commit fc49b0e2ac
1 changed files with 69 additions and 3 deletions
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72
libraries/mbed/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c
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@ -51,6 +51,20 @@ uint32_t pwmout_get_channel_route(pwmout_t *obj)
MBED_ASSERT(obj->channel != (PWMName) NC);
switch (obj->channel) {
#ifdef TIMER_ROUTEPEN_CC0PEN
case PWM_CH0:
return TIMER_ROUTEPEN_CC0PEN;
break;
case PWM_CH1:
return TIMER_ROUTEPEN_CC1PEN;
break;
case PWM_CH2:
return TIMER_ROUTEPEN_CC2PEN;
break;
case PWM_CH3:
return TIMER_ROUTEPEN_CC3PEN;
break;
#else
case PWM_CH0:
return TIMER_ROUTE_CC0PEN;
break;
@ -60,6 +74,7 @@ uint32_t pwmout_get_channel_route(pwmout_t *obj)
case PWM_CH2:
return TIMER_ROUTE_CC2PEN;
break;
#endif
default:
return 0;
}
@ -75,6 +90,15 @@ void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
}
}
#ifdef _TIMER_CC_CTRL_MODE_DEFAULT
void pwmout_enable(pwmout_t *obj, uint8_t enable){
PWM_TIMER->CC[obj->channel].CTRL = _TIMER_CC_CTRL_MODE_DEFAULT;
if (enable) {
/* Set mode to PWM */
PWM_TIMER->CC[obj->channel].CTRL = TIMER_CC_CTRL_MODE_PWM;
}
}
#else
void pwmout_enable(pwmout_t *obj, uint8_t enable)
{
/* Start with default CC (Compare/Capture) channel parameters */
@ -87,7 +111,7 @@ void pwmout_enable(pwmout_t *obj, uint8_t enable)
/* Configure CC channel */
TIMER_InitCC(PWM_TIMER, obj->channel, &timerCCInit);
}
#endif
void pwmout_init(pwmout_t *obj, PinName pin)
{
obj->channel = (PWMName) pinmap_peripheral(pin, PinMap_PWM);
@ -105,6 +129,32 @@ void pwmout_init(pwmout_t *obj, PinName pin)
/* Enable correct channel */
uint32_t routeloc = pwmout_get_channel_route(obj);
#ifdef _TIMER_ROUTELOC0_CC0LOC_LOC0
PWM_TIMER->ROUTEPEN |= routeloc;
blockSleepMode(EM1);
pwmout_enable(obj, true);
pwmout_enable_pins(obj, true);
switch (obj->channel) {
case PWM_CH0:
PWM_TIMER->ROUTELOC0 &= ~_TIMER_ROUTELOC0_CC0LOC_MASK;
PWM_TIMER->ROUTELOC0 |= pinmap_find_function(pin,PinMap_PWM) << _TIMER_ROUTELOC0_CC0LOC_SHIFT;
break;
case PWM_CH1:
PWM_TIMER->ROUTELOC0 &= ~_TIMER_ROUTELOC0_CC1LOC_MASK;
PWM_TIMER->ROUTELOC0 |= pinmap_find_function(pin,PinMap_PWM)<< _TIMER_ROUTELOC0_CC1LOC_SHIFT;
break;
case PWM_CH2:
PWM_TIMER->ROUTELOC0 &= ~_TIMER_ROUTELOC0_CC2LOC_MASK;
PWM_TIMER->ROUTELOC0 |= pinmap_find_function(pin,PinMap_PWM) << _TIMER_ROUTELOC0_CC2LOC_SHIFT;
break;
case PWM_CH3:
PWM_TIMER->ROUTELOC0 &= ~_TIMER_ROUTELOC0_CC3LOC_MASK;
PWM_TIMER->ROUTELOC0 |= pinmap_find_function(pin,PinMap_PWM) << _TIMER_ROUTELOC0_CC3LOC_SHIFT;
break;
default:
MBED_ASSERT(false);
}
#else
if(PWM_TIMER->ROUTE & routeloc) {
//This channel was already in use
//TODO: gracefully handle this case
@ -121,11 +171,27 @@ void pwmout_init(pwmout_t *obj, PinName pin)
/* Route correct channel to location 1 */
PWM_TIMER->ROUTE &= ~_TIMER_ROUTE_LOCATION_MASK;
PWM_TIMER->ROUTE |= PWM_ROUTE;
#endif
/* Set default 20ms frequency and 0ms pulse width */
pwmout_period(obj, 0.02);
}
#ifdef TIMER_ROUTEPEN_CC0PEN
void pwmout_free(pwmout_t *obj)
{
uint32_t routeloc = pwmout_get_channel_route(obj);
if(PWM_TIMER->ROUTEPEN & routeloc) {
//This channel was in use, so disable
PWM_TIMER->ROUTEPEN &= ~routeloc;
pwmout_enable_pins(obj, false);
unblockSleepMode(EM1);
//TODO: check if all channels are down, then switch off timer
} else {
//This channel was disabled already
}
}
#else
void pwmout_free(pwmout_t *obj)
{
uint32_t routeloc = pwmout_get_channel_route(obj);
@ -140,7 +206,7 @@ void pwmout_free(pwmout_t *obj)
//This channel was disabled already
}
}
#endif
void pwmout_write(pwmout_t *obj, float value)
{
if (value < 0.0f) {