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Merge pull request #1122 from stevew817/master 

[Silicon Labs] Bugfixes in PwmOut
pull/1128/head
Martin Kojtal 2015-05-21 09:37:32 +01:00
parent 1f6ad3fbb3 9ace27757c
commit 1abc53f8ed
1 changed files with 86 additions and 60 deletions
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146
libraries/mbed/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c
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@ -24,52 +24,31 @@
#include "pinmap.h"
#include "PeripheralPins.h"
#include "device_peripherals.h"
#include "sleepmodes.h"
#include "em_cmu.h"
#include "em_gpio.h"
#include "em_timer.h"
static int clockfreq;
static int prescaler_div;
static int pwm_clockfreq;
static int pwm_prescaler_div;
uint8_t pwmout_get_index(pwmout_t *obj)
{
return 0;
}
uint32_t pwmout_get_channel_route(pwmout_t *obj) {
MBED_ASSERT(obj->channel != (PWMName) NC);
void pwmout_preinit(pwmout_t *obj, PinName pin)
{
obj->channel = (PWMName) pinmap_peripheral(pin, PinMap_PWM);
obj->pin = pin;
MBED_ASSERT(obj->channel != (PWMName) NC);
}
void pwmout_init(pwmout_t *obj, PinName pin)
{
pwmout_preinit(obj, pin);
/* Enable correct channel */
switch (obj->channel) {
case PWM_CH0:
PWM_TIMER->ROUTE |= TIMER_ROUTE_CC0PEN;
break;
case PWM_CH1:
PWM_TIMER->ROUTE |= TIMER_ROUTE_CC1PEN;
break;
case PWM_CH2:
PWM_TIMER->ROUTE |= TIMER_ROUTE_CC2PEN;
break;
}
/* Route correct channel to location 1 */
PWM_TIMER->ROUTE |= PWM_ROUTE;
/*HFPER is the default clock we will use. It has a frequency of 14MHz*/
clockfreq = REFERENCE_FREQUENCY;
/* Set default 20ms frequency and 0ms pulse width */
pwmout_period(obj, 0.02);
switch (obj->channel) {
case PWM_CH0:
return TIMER_ROUTE_CC0PEN;
break;
case PWM_CH1:
return TIMER_ROUTE_CC1PEN;
break;
case PWM_CH2:
return TIMER_ROUTE_CC2PEN;
break;
default:
return 0;
}
}
void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
@ -84,24 +63,71 @@ void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
void pwmout_enable(pwmout_t *obj, uint8_t enable)
{
TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
/* Start with default CC (Compare/Capture) channel parameters */
TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT;
if (enable) {
/* Start with default CC (Compare/Capture) channel parameters */
TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT;
/* Set mode to PWM */
timerCCInit.mode = timerCCModePWM;
/* Configure CC channel */
TIMER_InitCC(PWM_TIMER, obj->channel, &timerCCInit);
TIMER_Init(PWM_TIMER, &timerInit);
} else {
timerInit.enable = false;
TIMER_Init(PWM_TIMER, &timerInit);
}
/* Configure CC channel */
TIMER_InitCC(PWM_TIMER, obj->channel, &timerCCInit);
}
void pwmout_init(pwmout_t *obj, PinName pin)
{
obj->channel = (PWMName) pinmap_peripheral(pin, PinMap_PWM);
obj->pin = pin;
MBED_ASSERT(obj->channel != (PWMName) NC);
/* Turn on clock */
CMU_ClockEnable(PWM_TIMER_CLOCK, true);
/* Turn on timer */
if(!(PWM_TIMER->STATUS & TIMER_STATUS_RUNNING)) {
TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
TIMER_Init(PWM_TIMER, &timerInit);
}
/* Enable correct channel */
uint32_t routeloc = pwmout_get_channel_route(obj);
if(PWM_TIMER->ROUTE & routeloc) {
//This channel was already in use
//TODO: gracefully handle this case
} else {
//This channel was unused up to now
PWM_TIMER->ROUTE |= routeloc;
blockSleepMode(EM1);
//TODO: check if any channel was up already, then don't re-init timer
pwmout_enable(obj, true);
pwmout_enable_pins(obj, true);
}
/* Route correct channel to location 1 */
PWM_TIMER->ROUTE &= ~_TIMER_ROUTE_LOCATION_MASK;
PWM_TIMER->ROUTE |= PWM_ROUTE;
/*HFPER is the default clock we will use. It has a frequency of 14MHz*/
pwm_clockfreq = REFERENCE_FREQUENCY;
/* Set default 20ms frequency and 0ms pulse width */
pwmout_period(obj, 0.02);
}
void pwmout_free(pwmout_t *obj) {
uint32_t routeloc = pwmout_get_channel_route(obj);
if(PWM_TIMER->ROUTE & routeloc) {
//This channel was in use, so disable
PWM_TIMER->ROUTE &= ~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
}
}
void pwmout_write(pwmout_t *obj, float value)
{
@ -111,7 +137,7 @@ void pwmout_write(pwmout_t *obj, float value)
value = 1;
}
float pulse_period_in_s = obj->period_cycles / (float) clockfreq;
float pulse_period_in_s = obj->period_cycles / (float) pwm_clockfreq;
pwmout_pulsewidth(obj, value * pulse_period_in_s);
}
@ -127,17 +153,17 @@ void pwmout_period(pwmout_t *obj, float seconds)
// This gives us max resolution for a given period
//The value of the top register if prescaler is set to 0
int cycles = clockfreq * seconds;
prescaler_div = 0;
int cycles = pwm_clockfreq * seconds;
pwm_prescaler_div = 0;
//The top register is only 16 bits, so we keep dividing till we are below 0xFFFF
while (cycles > 0xFFFF) {
cycles /= 2;
prescaler_div++;
pwm_prescaler_div++;
//Max prescaler_div supported is 10
if (prescaler_div > 10) {
prescaler_div = 10;
//Max pwm_prescaler_div supported is 10
if (pwm_prescaler_div > 10) {
pwm_prescaler_div = 10;
cycles = 0xFFFF; //Set it to max possible value;
break;
}
@ -146,7 +172,7 @@ void pwmout_period(pwmout_t *obj, float seconds)
obj->period_cycles = cycles;
//Set prescaler
PWM_TIMER->CTRL = (PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (prescaler_div << _TIMER_CTRL_PRESC_SHIFT);
PWM_TIMER->CTRL = (PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (pwm_prescaler_div << _TIMER_CTRL_PRESC_SHIFT);
/* Set Top Value, which controls the PWM period */
TIMER_TopSet(PWM_TIMER, obj->period_cycles);
@ -164,7 +190,7 @@ void pwmout_period_us(pwmout_t *obj, int us)
void pwmout_pulsewidth(pwmout_t *obj, float seconds)
{
obj->width_cycles = clockfreq * seconds;
obj->width_cycles = pwm_clockfreq * seconds;
TIMER_CompareBufSet(PWM_TIMER, obj->channel, obj->width_cycles);
}