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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2017-12-04 Haley the first version
*/
#include <rtthread.h>
#include <rtdevice.h>
#include "am_mcu_apollo.h"
#include "board.h"
#ifdef RT_USING_PWM
// LED3 is pin 19
#define AM_BSP_GPIO_PWM_LED 19
#define AM_BSP_GPIO_CFG_PWM_LED AM_HAL_PIN_19_TCTB1
#define AM_BSP_PWM_LED_TIMER 1
#define AM_BSP_PWM_LED_TIMER_SEG AM_HAL_CTIMER_TIMERB
#define AM_BSP_PWM_LED_TIMER_INT AM_HAL_CTIMER_INT_TIMERB1
/**
* @brief LED brightness profile
*
* This function define LED brightness profile
*
* @return None.
*/
volatile uint32_t g_ui32Index = 0;
const uint32_t g_pui32Brightness[64] =
{
1, 1, 1, 2, 3, 4, 6, 8,
10, 12, 14, 17, 20, 23, 25, 28,
31, 35, 38, 40, 43, 46, 49, 51,
53, 55, 57, 59, 60, 61, 62, 62,
63, 62, 62, 61, 60, 59, 57, 55,
53, 51, 49, 46, 43, 40, 38, 35,
32, 28, 25, 23, 20, 17, 14, 12,
10, 8, 6, 4, 3, 2, 1, 1
};
/**
* @brief Interrupt handler for the Timer
*
* This function is Interrupt handler for the Timer
*
* @return None.
*/
void am_ctimer_isr(void)
{
/* Clear the interrupt that got us here */
am_hal_ctimer_int_clear(AM_BSP_PWM_LED_TIMER_INT);
/* Now set new PWM half-period for the LED */
am_hal_ctimer_period_set(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG,
64, g_pui32Brightness[g_ui32Index]);
/* Set up the LED duty cycle for the next pulse */
g_ui32Index = (g_ui32Index + 1) % 64;
}
/**
* @brief Initialize the PWM
*
* This function initialize the PWM
*
* @return 0.
*/
int rt_hw_pwm_init(void)
{
/* init pwm gpio */
am_hal_gpio_pin_config(AM_BSP_GPIO_PWM_LED, AM_BSP_GPIO_CFG_PWM_LED);
/* Configure a timer to drive the LED */
am_hal_ctimer_config_single(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG,
(AM_HAL_CTIMER_FN_PWM_REPEAT |
AM_HAL_CTIMER_XT_2_048KHZ |
AM_HAL_CTIMER_INT_ENABLE |
AM_HAL_CTIMER_PIN_ENABLE));
/* Set up initial timer period */
am_hal_ctimer_period_set(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG,
64, 32);
/* Enable interrupts for the Timer we are using on this board */
am_hal_ctimer_int_enable(AM_BSP_PWM_LED_TIMER_INT);
am_hal_interrupt_enable(AM_HAL_INTERRUPT_CTIMER);
/* Start the timer */
am_hal_ctimer_start(AM_BSP_PWM_LED_TIMER, AM_BSP_PWM_LED_TIMER_SEG);
rt_kprintf("pwm_init!\n");
return 0;
}
#ifdef RT_USING_COMPONENTS_INIT
INIT_BOARD_EXPORT(rt_hw_pwm_init);
#endif
#endif
/*@}*/
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