+++ /dev/null
-/* 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 "mbed_assert.h"
-#include "pwmout_api.h"
-#include "cmsis.h"
-#include "pinmap.h"
-#include "PeripheralPins.h" // For the Peripheral to Pin Definitions found in the individual Target's Platform
-
-#define TCR_CNT_EN 0x00000001
-#define TCR_RESET 0x00000002
-
-typedef struct {
- uint8_t timer;
- uint8_t mr;
-} timer_mr;
-
-static timer_mr pwm_timer_map[11] = {
- {0, 0}, {0, 1}, {0, 2},
- {1, 0}, {1, 1},
- {2, 0}, {2, 1}, {2, 2},
- {3, 0}, {3, 1}, {3, 2},
-};
-
-static LPC_CTxxBx_Type *Timers[4] = {
- LPC_CT16B0, LPC_CT16B1,
- LPC_CT32B0, LPC_CT32B1
-};
-
-void pwmout_init(pwmout_t* obj, PinName pin) {
- // determine the channel
- PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
- MBED_ASSERT(pwm != (PWMName)NC);
-
- obj->pwm = pwm;
-
- // Timer registers
- timer_mr tid = pwm_timer_map[pwm];
- LPC_CTxxBx_Type *timer = Timers[tid.timer];
-
- // Disable timer
- timer->TCR = 0;
-
- // Power the correspondent timer
- LPC_SYSCON->SYSAHBCLKCTRL |= 1 << (tid.timer + 7);
-
- /* Enable PWM function */
- timer->PWMC = (1 << 3)|(1 << 2)|(1 << 1)|(1 << 0);
-
- /* Reset Functionality on MR3 controlling the PWM period */
- timer->MCR = 1 << 10;
-
- // default to 20ms: standard for servos, and fine for e.g. brightness control
- pwmout_period_ms(obj, 20);
- pwmout_write (obj, 0);
-
- // Wire pinout
- pinmap_pinout(pin, PinMap_PWM);
-}
-
-void pwmout_free(pwmout_t* obj) {
- // [TODO]
-}
-
-void pwmout_write(pwmout_t* obj, float value) {
- if (value < 0.0f) {
- value = 0.0;
- } else if (value > 1.0f) {
- value = 1.0;
- }
-
- timer_mr tid = pwm_timer_map[obj->pwm];
- LPC_CTxxBx_Type *timer = Timers[tid.timer];
- uint32_t t_off = timer->MR3 - (uint32_t)((float)(timer->MR3) * value);
-
- timer->MR[tid.mr] = t_off;
-}
-
-float pwmout_read(pwmout_t* obj) {
- timer_mr tid = pwm_timer_map[obj->pwm];
- LPC_CTxxBx_Type *timer = Timers[tid.timer];
-
- float v = (float)(timer->MR3 - timer->MR[tid.mr]) / (float)(timer->MR3);
- return (v > 1.0f) ? (1.0f) : (v);
-}
-
-void pwmout_period(pwmout_t* obj, float seconds) {
- pwmout_period_us(obj, seconds * 1000000.0f);
-}
-
-void pwmout_period_ms(pwmout_t* obj, int ms) {
- pwmout_period_us(obj, ms * 1000);
-}
-
-// Set the PWM period, keeping the duty cycle the same.
-void pwmout_period_us(pwmout_t* obj, int us) {
- int i = 0;
- uint32_t period_ticks = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000);
-
- timer_mr tid = pwm_timer_map[obj->pwm];
- LPC_CTxxBx_Type *timer = Timers[tid.timer];
- uint32_t old_period_ticks = timer->MR3;
-
- // for 16bit timer, set prescaler to avoid overflow
- if (timer == LPC_CT16B0 || timer == LPC_CT16B1) {
- uint16_t high_period_ticks = period_ticks >> 16;
- timer->PR = high_period_ticks;
- period_ticks /= (high_period_ticks + 1);
- }
-
- timer->TCR = TCR_RESET;
- timer->MR3 = period_ticks;
-
- // Scale the pulse width to preserve the duty ratio
- if (old_period_ticks > 0) {
- for (i=0; i<3; i++) {
- uint32_t t_off = period_ticks - (uint32_t)(((uint64_t)timer->MR[i] * (uint64_t)period_ticks) / (uint64_t)old_period_ticks);
- timer->MR[i] = t_off;
- }
- }
- timer->TCR = TCR_CNT_EN;
-}
-
-void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
- pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
-}
-
-void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
- pwmout_pulsewidth_us(obj, ms * 1000);
-}
-
-void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
- timer_mr tid = pwm_timer_map[obj->pwm];
- LPC_CTxxBx_Type *timer = Timers[tid.timer];
- uint32_t t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000 / (timer->PR + 1));
-
- timer->TCR = TCR_RESET;
- if (t_on > timer->MR3) {
- pwmout_period_us(obj, us);
- t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000 / (timer->PR + 1));
- }
- uint32_t t_off = timer->MR3 - t_on;
- timer->MR[tid.mr] = t_off;
- timer->TCR = TCR_CNT_EN;
-}