[11U68]fix P0_11 to use GPIO
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targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c
- Committer:
- mbed_official
- Date:
- 2015-05-22
- Revision:
- 548:1abac31e188e
- Parent:
- 544:1af5f1c39e80
- Child:
- 554:edd95c0879f8
File content as of revision 548:1abac31e188e:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * 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 int pwm_clockfreq; static int pwm_prescaler_div; uint32_t pwmout_get_channel_route(pwmout_t *obj) { MBED_ASSERT(obj->channel != (PWMName) NC); 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) { 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) { /* Start with default CC (Compare/Capture) channel parameters */ TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT; if (enable) { /* Set mode to PWM */ timerCCInit.mode = timerCCModePWM; } /* 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) { if (value < 0.0f) { value = 0; } else if (value > 1.0f) { value = 1; } float pulse_period_in_s = obj->period_cycles / (float) pwm_clockfreq; pwmout_pulsewidth(obj, value * pulse_period_in_s); } float pwmout_read(pwmout_t *obj) { return obj->width_cycles / (float) obj->period_cycles; } // Set the PWM period, keeping the absolute pulse width 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 = 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; 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; } } obj->period_cycles = cycles; //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_TopSet(PWM_TIMER, obj->period_cycles); } 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_ms(obj, us / 1000.0f); } void pwmout_pulsewidth(pwmout_t *obj, float seconds) { obj->width_cycles = pwm_clockfreq * seconds; TIMER_CompareBufSet(PWM_TIMER, obj->channel, obj->width_cycles); } void pwmout_pulsewidth_ms(pwmout_t *obj, int ms) { pwmout_pulsewidth(obj, ms / 1000.0f); } void pwmout_pulsewidth_us(pwmout_t *obj, int us) { pwmout_pulsewidth_ms(obj, us / 1000.0f); } #endif