121 lines
3.5 KiB
C
121 lines
3.5 KiB
C
/*
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* File :_pwm.c
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* This file is part of RT-Thread RTOS
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* COPYRIGHT (C) 2006 - 2017, RT-Thread Development Team
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Change Logs:
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* Date Author Notes
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* 2017-12-04 Haley the first version
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*/
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#include <rtthread.h>
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#include <rtdevice.h>
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#include "am_mcu_apollo.h"
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#include "board.h"
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#ifdef RT_USING_PWM
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// LED3 is pin 19
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#define AM_BSP_GPIO_PWM_LED 19
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#define AM_BSP_GPIO_CFG_PWM_LED AM_HAL_PIN_19_TCTB1
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#define AM_BSP_PWM_LED_TIMER 1
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#define AM_BSP_PWM_LED_TIMER_SEG AM_HAL_CTIMER_TIMERB
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#define AM_BSP_PWM_LED_TIMER_INT AM_HAL_CTIMER_INT_TIMERB1
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/**
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* @brief LED brightness profile
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*
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* This function define LED brightness profile
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*
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* @return None.
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*/
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volatile uint32_t g_ui32Index = 0;
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const uint32_t g_pui32Brightness[64] =
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{
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1, 1, 1, 2, 3, 4, 6, 8,
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10, 12, 14, 17, 20, 23, 25, 28,
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31, 35, 38, 40, 43, 46, 49, 51,
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53, 55, 57, 59, 60, 61, 62, 62,
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63, 62, 62, 61, 60, 59, 57, 55,
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53, 51, 49, 46, 43, 40, 38, 35,
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32, 28, 25, 23, 20, 17, 14, 12,
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10, 8, 6, 4, 3, 2, 1, 1
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};
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/**
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* @brief Interrupt handler for the Timer
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*
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* This function is Interrupt handler for the Timer
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*
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* @return None.
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*/
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void am_ctimer_isr(void)
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{
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/* Clear the interrupt that got us here */
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am_hal_ctimer_int_clear(AM_BSP_PWM_LED_TIMER_INT);
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/* Now set new PWM half-period for the LED */
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am_hal_ctimer_period_set(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG,
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64, g_pui32Brightness[g_ui32Index]);
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/* Set up the LED duty cycle for the next pulse */
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g_ui32Index = (g_ui32Index + 1) % 64;
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}
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/**
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* @brief Initialize the PWM
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*
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* This function initialize the PWM
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*
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* @return 0.
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*/
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int rt_hw_pwm_init(void)
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{
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/* init pwm gpio */
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am_hal_gpio_pin_config(AM_BSP_GPIO_PWM_LED, AM_BSP_GPIO_CFG_PWM_LED);
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/* Configure a timer to drive the LED */
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am_hal_ctimer_config_single(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG,
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(AM_HAL_CTIMER_FN_PWM_REPEAT |
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AM_HAL_CTIMER_XT_2_048KHZ |
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AM_HAL_CTIMER_INT_ENABLE |
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AM_HAL_CTIMER_PIN_ENABLE));
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/* Set up initial timer period */
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am_hal_ctimer_period_set(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG,
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64, 32);
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/* Enable interrupts for the Timer we are using on this board */
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am_hal_ctimer_int_enable(AM_BSP_PWM_LED_TIMER_INT);
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am_hal_interrupt_enable(AM_HAL_INTERRUPT_CTIMER);
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/* Start the timer */
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am_hal_ctimer_start(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG);
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rt_kprintf("pwm_init!\n");
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return 0;
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}
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#ifdef RT_USING_COMPONENTS_INIT
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INIT_BOARD_EXPORT(rt_hw_pwm_init);
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#endif
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#endif
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/*@}*/
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