Johannes Stratmann
added prescaler for 16 bit pwm in LPC1347 target
Fork of
mbed-dev
by 
mbed official
Diff: targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c
- Revision:
- 144:ef7eb2e8f9f7
- Parent:
- 50:a417edff4437
--- a/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c Tue Aug 02 14:07:36 2016 +0000
+++ b/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c Fri Sep 02 15:07:44 2016 +0100
@@ -1,358 +1,355 @@
-/***************************************************************************//**
- * @file pwmout_api.c
- *******************************************************************************
- * @section License
- * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
- *******************************************************************************
- *
- * Permission is granted to anyone to use this software for any purpose,
- * including commercial applications, and to alter it and redistribute it
- * freely, subject to the following restrictions:
- *
- * 1. The origin of this software must not be misrepresented; you must not
- * claim that you wrote the original software.
- * 2. Altered source versions must be plainly marked as such, and must not be
- * misrepresented as being the original software.
- * 3. This notice may not be removed or altered from any source distribution.
- *
- * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
- * obligation to support this Software. Silicon Labs is providing the
- * Software "AS IS", with no express or implied warranties of any kind,
- * including, but not limited to, any implied warranties of merchantability
- * or fitness for any particular purpose or warranties against infringement
- * of any proprietary rights of a third party.
- *
- * Silicon Labs will not be liable for any consequential, incidental, or
- * special damages, or any other relief, or for any claim by any third party,
- * arising from your use of this Software.
- *
- ******************************************************************************/
-
-#include "device.h"
-#include "clocking.h"
-#if DEVICE_PWMOUT
-
-#include "mbed_assert.h"
-#include "pwmout_api.h"
-#include "cmsis.h"
-#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 pwm_prescaler_div;
-
-float pwmout_calculate_duty(uint32_t width_cycles, uint32_t period_cycles);
-void pwmout_write_channel(uint32_t channel, float value);
-
-uint32_t pwmout_get_channel_route(uint32_t channel)
-{
- MBED_ASSERT(channel != (PWMName) NC);
-
- switch (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;
- case PWM_CH1:
- return TIMER_ROUTE_CC1PEN;
- break;
- case PWM_CH2:
- return TIMER_ROUTE_CC2PEN;
- break;
-#endif
- default:
- return 0;
- }
-}
-
-/*
-* Disables the route location given. Returns true if it was enabled, false if it wasn't.
-*/
-bool pwmout_disable_channel_route(uint32_t routeloc) {
-#ifdef TIMER_ROUTEPEN_CC0PEN
- if(PWM_TIMER->ROUTEPEN & routeloc) {
- //This channel was in use, so disable
- PWM_TIMER->ROUTEPEN &= ~routeloc;
- return true;
- }
-#else
- if(PWM_TIMER->ROUTE & routeloc) {
- //This channel was in use, so disable
- PWM_TIMER->ROUTE &= ~routeloc;
- return true;
- }
-#endif
- return false;
-}
-
-/*
-* Check if a channel is active
-*/
-bool pwmout_channel_route_active(uint32_t routeloc) {
-#ifdef TIMER_ROUTEPEN_CC0PEN
- if(PWM_TIMER->ROUTEPEN & routeloc) {
- return true;
- }
-#else
- if(PWM_TIMER->ROUTE & routeloc) {
- return true;
- }
-#endif
- return false;
-}
-
-/*
-* Set the given route PEN flag
-*/
-void pwmout_set_channel_route(uint32_t routeloc) {
-#ifdef TIMER_ROUTEPEN_CC0PEN
- PWM_TIMER->ROUTEPEN |= routeloc;
-#else
- PWM_TIMER->ROUTE |= routeloc;
-#endif
-}
-
-/*
-* Check if all routes are disabled
-*/
-bool pwmout_all_inactive(void) {
-#ifdef TIMER_ROUTEPEN_CC0PEN
- if(PWM_TIMER->ROUTEPEN == _TIMER_ROUTEPEN_RESETVALUE) {
- return true;
- }
-#else
- if(PWM_TIMER->ROUTE == PWM_ROUTE) {
- return true;
- }
-#endif
- return false;
-}
-
-void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
-{
- if (enable) {
- pin_mode(obj->pin, PushPull);
- } else {
- // TODO_LP return PinMode to the previous state
- pin_mode(obj->pin, Disabled);
- }
-}
-
-void pwmout_enable(pwmout_t *obj, uint8_t enable){
- if (enable) {
- // Set mode to PWM
- PWM_TIMER->CC[obj->channel].CTRL = TIMER_CC_CTRL_MODE_PWM;
- } else {
- // Set mode to default (== disabled)
- PWM_TIMER->CC[obj->channel].CTRL = _TIMER_CC_CTRL_MODE_DEFAULT;
- }
-}
-
-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);
- }
-
- // Set route enable
- if(pwmout_channel_route_active(pwmout_get_channel_route(obj->channel))) {
- //This channel was already in use
- //TODO: gracefully handle this case. mbed_error?
- return;
- } else {
- pwmout_set_channel_route(pwmout_get_channel_route(obj->channel));
- blockSleepMode(EM1);
- pwmout_enable(obj, true);
- pwmout_enable_pins(obj, true);
- }
-
- // Set route location
-#ifdef _TIMER_ROUTELOC0_CC0LOC_LOC0
- 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
- // On P1, the route location is statically defined for the entire timer.
- 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);
-}
-
-void pwmout_free(pwmout_t *obj)
-{
- if(pwmout_disable_channel_route(pwmout_get_channel_route(obj->channel))) {
- //Channel was previously enabled, so do housekeeping
- unblockSleepMode(EM1);
- } else {
- //This channel was disabled already
- }
-
- pwmout_enable_pins(obj, false);
-
- if(pwmout_all_inactive()) {
- //Stop timer
- PWM_TIMER->CMD = TIMER_CMD_STOP;
- while(PWM_TIMER->STATUS & TIMER_STATUS_RUNNING);
-
- //Disable clock
- CMU_ClockEnable(PWM_TIMER_CLOCK, false);
- }
-}
-
-void pwmout_write(pwmout_t *obj, float value)
-{
- pwmout_write_channel(obj->channel, value);
-}
-
-void pwmout_write_channel(uint32_t channel, float value) {
- uint32_t width_cycles = 0;
- if (value < 0.0f) {
- width_cycles = 0;
- } else if (value >= 1.0f) {
- width_cycles = PWM_TIMER->TOPB + 1;
- } else {
- width_cycles = (uint16_t)((float)PWM_TIMER->TOPB * value);
- }
-
- TIMER_CompareBufSet(PWM_TIMER, channel, width_cycles);
-}
-
-float pwmout_read(pwmout_t *obj)
-{
- return pwmout_calculate_duty(TIMER_CaptureGet(PWM_TIMER, obj->channel), TIMER_TopGet(PWM_TIMER));
-}
-
-float pwmout_calculate_duty(uint32_t width_cycles, uint32_t period_cycles) {
- if(width_cycles > period_cycles) {
- return 1.0f;
- }
- else if (width_cycles == 0) {
- return 0.0f;
- }
- else {
- return (float) width_cycles / (float) period_cycles;
- }
-}
-
-// Set the PWM period, keeping the duty cycle the same.
-void pwmout_period(pwmout_t *obj, float seconds)
-{
- // Find the lowest prescaler divider possible.
- // This gives us max resolution for a given period
-
- //The value of the top register if prescaler is set to 0
- int cycles = REFERENCE_FREQUENCY * 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;
- pwm_prescaler_div++;
-
- //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;
- }
- }
-
- //Check if anything changed
- if(((PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) == (pwm_prescaler_div << _TIMER_CTRL_PRESC_SHIFT)) && (TIMER_TopGet(PWM_TIMER) == cycles)) return;
-
- //Save previous period for recalculation of duty cycles
- uint32_t previous_period_cycles = PWM_TIMER->TOPB;
-
- //Set prescaler
- 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_TopBufSet(PWM_TIMER, cycles);
-
- //For each active channel, re-calculate the compare value
- uint32_t channel = 0;
- while(pwmout_get_channel_route(channel) != 0) {
- if(pwmout_channel_route_active(channel)) {
- //recalc and reset compare value
- pwmout_write_channel(channel, pwmout_calculate_duty(PWM_TIMER->CC[channel].CCVB, previous_period_cycles));
- }
- channel++;
- }
-}
-
-void pwmout_period_ms(pwmout_t *obj, int ms)
-{
- pwmout_period(obj, ms / 1000.0f);
-}
-
-void pwmout_period_us(pwmout_t *obj, int us)
-{
- pwmout_period(obj, us / 1000000.0f);
-}
-
-void pwmout_pulsewidth(pwmout_t *obj, float seconds)
-{
- uint16_t width_cycles = (uint16_t) (((float) (REFERENCE_FREQUENCY >> pwm_prescaler_div)) * seconds);
- TIMER_CompareBufSet(PWM_TIMER, obj->channel, width_cycles);
-}
-
-void pwmout_pulsewidth_ms(pwmout_t *obj, int ms)
-{
- uint16_t width_cycles = (uint16_t) ((REFERENCE_FREQUENCY >> pwm_prescaler_div) * ms) / 1000;
- TIMER_CompareBufSet(PWM_TIMER, obj->channel, width_cycles);
-}
-
-void pwmout_pulsewidth_us(pwmout_t *obj, int us)
-{
- uint16_t width_cycles = (uint16_t) ((REFERENCE_FREQUENCY >> pwm_prescaler_div) * us) / 1000000;
- TIMER_CompareBufSet(PWM_TIMER, obj->channel, width_cycles);
-}
-
-#endif
+/***************************************************************************//**
+ * @file pwmout_api.c
+ *******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
+ *******************************************************************************
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ ******************************************************************************/
+
+#include "device.h"
+#include "clocking.h"
+#if DEVICE_PWMOUT
+
+#include "mbed_assert.h"
+#include "pwmout_api.h"
+#include "cmsis.h"
+#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 uint32_t pwm_prescaler_div;
+
+float pwmout_calculate_duty(uint32_t width_cycles, uint32_t period_cycles);
+void pwmout_write_channel(uint32_t channel, float value);
+
+uint32_t pwmout_get_channel_route(uint32_t channel)
+{
+ MBED_ASSERT(channel != (PWMName) NC);
+
+ switch (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;
+ case PWM_CH1:
+ return TIMER_ROUTE_CC1PEN;
+ break;
+ case PWM_CH2:
+ return TIMER_ROUTE_CC2PEN;
+ break;
+#endif
+ default:
+ return 0;
+ }
+}
+
+/*
+* Disables the route location given. Returns true if it was enabled, false if it wasn't.
+*/
+bool pwmout_disable_channel_route(uint32_t routeloc) {
+#ifdef TIMER_ROUTEPEN_CC0PEN
+ if(PWM_TIMER->ROUTEPEN & routeloc) {
+ //This channel was in use, so disable
+ PWM_TIMER->ROUTEPEN &= ~routeloc;
+ return true;
+ }
+#else
+ if(PWM_TIMER->ROUTE & routeloc) {
+ //This channel was in use, so disable
+ PWM_TIMER->ROUTE &= ~routeloc;
+ return true;
+ }
+#endif
+ return false;
+}
+
+/*
+* Check if a channel is active
+*/
+bool pwmout_channel_route_active(uint32_t routeloc) {
+#ifdef TIMER_ROUTEPEN_CC0PEN
+ if(PWM_TIMER->ROUTEPEN & routeloc) {
+ return true;
+ }
+#else
+ if(PWM_TIMER->ROUTE & routeloc) {
+ return true;
+ }
+#endif
+ return false;
+}
+
+/*
+* Set the given route PEN flag
+*/
+void pwmout_set_channel_route(uint32_t routeloc) {
+#ifdef TIMER_ROUTEPEN_CC0PEN
+ PWM_TIMER->ROUTEPEN |= routeloc;
+#else
+ PWM_TIMER->ROUTE |= routeloc;
+#endif
+}
+
+/*
+* Check if all routes are disabled
+*/
+bool pwmout_all_inactive(void) {
+#ifdef TIMER_ROUTEPEN_CC0PEN
+ if(PWM_TIMER->ROUTEPEN == _TIMER_ROUTEPEN_RESETVALUE) {
+ return true;
+ }
+#else
+ if(PWM_TIMER->ROUTE & (TIMER_ROUTE_CC0PEN | TIMER_ROUTE_CC1PEN | TIMER_ROUTE_CC2PEN)) {
+ return true;
+ }
+#endif
+ return false;
+}
+
+void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
+{
+ if (enable) {
+ pin_mode(obj->pin, PushPull);
+ } else {
+ // TODO_LP return PinMode to the previous state
+ pin_mode(obj->pin, Disabled);
+ }
+}
+
+void pwmout_enable(pwmout_t *obj, uint8_t enable){
+ if (enable) {
+ // Set mode to PWM
+ PWM_TIMER->CC[obj->channel].CTRL = TIMER_CC_CTRL_MODE_PWM;
+ } else {
+ // Set mode to default (== disabled)
+ PWM_TIMER->CC[obj->channel].CTRL = _TIMER_CC_CTRL_MODE_DEFAULT;
+ }
+}
+
+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);
+ }
+
+ // Set route enable
+ if(pwmout_channel_route_active(pwmout_get_channel_route(obj->channel))) {
+ //This channel was already in use
+ //TODO: gracefully handle this case. mbed_error?
+ return;
+ } else {
+ pwmout_set_channel_route(pwmout_get_channel_route(obj->channel));
+ blockSleepMode(EM1);
+ pwmout_enable(obj, true);
+ pwmout_enable_pins(obj, true);
+ }
+
+ // Set route location
+#ifdef _TIMER_ROUTELOC0_CC0LOC_LOC0
+ 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
+ // On P1, the route location is statically defined for the entire timer.
+ PWM_TIMER->ROUTE &= ~_TIMER_ROUTE_LOCATION_MASK;
+if(pwmout_all_inactive()) {
+ PWM_TIMER->ROUTE |= pinmap_find_function(pin,PinMap_PWM) << _TIMER_ROUTE_LOCATION_SHIFT;
+ } else {
+ MBED_ASSERT((pinmap_find_function(pin,PinMap_PWM) << _TIMER_ROUTE_LOCATION_SHIFT) == (PWM_TIMER->ROUTE & _TIMER_ROUTE_LOCATION_MASK));
+ }
+#endif
+
+ // Set default 20ms frequency and 0ms pulse width
+ pwmout_period(obj, 0.02);
+}
+
+void pwmout_free(pwmout_t *obj)
+{
+ if(pwmout_disable_channel_route(pwmout_get_channel_route(obj->channel))) {
+ //Channel was previously enabled, so do housekeeping
+ unblockSleepMode(EM1);
+ } else {
+ //This channel was disabled already
+ }
+
+ pwmout_enable_pins(obj, false);
+
+ if(pwmout_all_inactive()) {
+ //Stop timer
+ PWM_TIMER->CMD = TIMER_CMD_STOP;
+ while(PWM_TIMER->STATUS & TIMER_STATUS_RUNNING);
+
+ //Disable clock
+ CMU_ClockEnable(PWM_TIMER_CLOCK, false);
+ }
+}
+
+void pwmout_write(pwmout_t *obj, float value)
+{
+ pwmout_write_channel(obj->channel, value);
+}
+
+void pwmout_write_channel(uint32_t channel, float value) {
+ uint32_t width_cycles = 0;
+ if (value < 0.0f) {
+ width_cycles = 0;
+ } else if (value >= 1.0f) {
+ width_cycles = PWM_TIMER->TOPB + 1;
+ } else {
+ width_cycles = (uint16_t)((float)PWM_TIMER->TOPB * value);
+ }
+
+ TIMER_CompareBufSet(PWM_TIMER, channel, width_cycles);
+}
+
+float pwmout_read(pwmout_t *obj)
+{
+ return pwmout_calculate_duty(TIMER_CaptureGet(PWM_TIMER, obj->channel), TIMER_TopGet(PWM_TIMER));
+}
+
+float pwmout_calculate_duty(uint32_t width_cycles, uint32_t period_cycles) {
+ if(width_cycles > period_cycles) {
+ return 1.0f;
+ }
+ else if (width_cycles == 0) {
+ return 0.0f;
+ }
+ else {
+ return (float) width_cycles / (float) period_cycles;
+ }
+}
+
+// Set the PWM period, keeping the duty cycle the same.
+void pwmout_period(pwmout_t *obj, float seconds)
+{
+ // Find the lowest prescaler divider possible.
+ // This gives us max resolution for a given period
+
+ //The value of the top register if prescaler is set to 0
+ uint32_t cycles = (uint32_t)REFERENCE_FREQUENCY * 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;
+ pwm_prescaler_div++;
+
+ //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;
+ }
+ }
+
+ //Check if anything changed
+ if(((PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) == (pwm_prescaler_div << _TIMER_CTRL_PRESC_SHIFT)) && (TIMER_TopGet(PWM_TIMER) == cycles)) return;
+
+ //Save previous period for recalculation of duty cycles
+ uint32_t previous_period_cycles = PWM_TIMER->TOPB;
+
+ //Set prescaler
+ 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_TopBufSet(PWM_TIMER, cycles);
+
+ //For each active channel, re-calculate the compare value
+ uint32_t channel = 0;
+ while(pwmout_get_channel_route(channel) != 0) {
+ if(pwmout_channel_route_active(channel)) {
+ //recalc and reset compare value
+ pwmout_write_channel(channel, pwmout_calculate_duty(PWM_TIMER->CC[channel].CCVB, previous_period_cycles));
+ }
+ channel++;
+ }
+}
+
+void pwmout_period_ms(pwmout_t *obj, int ms)
+{
+ pwmout_period(obj, ms / 1000.0f);
+}
+
+void pwmout_period_us(pwmout_t *obj, int us)
+{
+ pwmout_period(obj, us / 1000000.0f);
+}
+
+void pwmout_pulsewidth(pwmout_t *obj, float seconds)
+{
+ uint16_t width_cycles = (uint16_t) (((float) (REFERENCE_FREQUENCY >> pwm_prescaler_div)) * seconds);
+ TIMER_CompareBufSet(PWM_TIMER, obj->channel, width_cycles);
+}
+
+void pwmout_pulsewidth_ms(pwmout_t *obj, int ms)
+{
+ uint16_t width_cycles = (uint16_t) ((REFERENCE_FREQUENCY >> pwm_prescaler_div) * ms) / 1000;
+ TIMER_CompareBufSet(PWM_TIMER, obj->channel, width_cycles);
+}
+
+void pwmout_pulsewidth_us(pwmout_t *obj, int us)
+{
+ uint16_t width_cycles = (uint16_t) ((REFERENCE_FREQUENCY >> pwm_prescaler_div) * us) / 1000000;
+ TIMER_CompareBufSet(PWM_TIMER, obj->channel, width_cycles);
+}
+
+#endif