本帖最后由 lishuihua 于 2024-7-21 16:54 编辑
基本原理是通过改变PWM占空比来实现小灯从暗到亮变化，即呼吸效果。
在上一篇测评的基础上，增加一个TCPWM配置，配置CLOCK SIGNAL为16bit Divider 0 clik，配置PWM Mode为PWM模式，输出PWM到P5[2]，即小灯LED4位置。
完整代码如下：
#include "cyhal.h"
#include "cybsp.h"
#include "cy_retarget_io.h"
/*******************************************************************************
* Macros
*******************************************************************************/
/* LED blink timer clock value in Hz */
#define LED_BLINK_TIMER_CLOCK_HZ (10000)
/* LED blink timer period value */
#define LED_BLINK_TIMER_PERIOD (9)
/*******************************************************************************
* Global Variables
*******************************************************************************/
bool timer_interrupt_flag = false;
bool led_blink_active_flag = true;
/* Variable for storing character read from terminal */
uint8_t uart_read_value;
/* Timer object used for blinking the LED */
cyhal_timer_t led_blink_timer;
/* variables related to pwm*/
uint16_t timer_count = 2000;
cyhal_pwm_t pwm_led2_control;
/*******************************************************************************
* Function Prototypes
*******************************************************************************/
void timer_init(void);
static void isr_timer(void *callback_arg, cyhal_timer_event_t event);
/*******************************************************************************
* Function Name: main
********************************************************************************
* Summary:
* This is the main function. It sets up a timer to trigger a periodic interrupt.
* The main while loop checks for the status of a flag set by the interrupt and
* toggles an LED at 1Hz to create an LED blinky. Will be achieving the 1Hz Blink
* rate based on the The LED_BLINK_TIMER_CLOCK_HZ and LED_BLINK_TIMER_PERIOD
* Macros,i.e. (LED_BLINK_TIMER_PERIOD + 1) / LED_BLINK_TIMER_CLOCK_HZ = X ,Here,
* X denotes the desired blink rate. The while loop also checks whether the
* 'Enter' key was pressed and stops/restarts LED blinking.
*
* Parameters:
* none
*
* Return:
* int
*
*******************************************************************************/
int main(void)
{
cy_rslt_t result;
#if defined (CY_DEVICE_SECURE)
cyhal_wdt_t wdt_obj;
/* Clear watchdog timer so that it doesn't trigger a reset */
result = cyhal_wdt_init(&wdt_obj, cyhal_wdt_get_max_timeout_ms());
CY_ASSERT(CY_RSLT_SUCCESS == result);
cyhal_wdt_free(&wdt_obj);
#endif /* #if defined (CY_DEVICE_SECURE) */
/* Initialize the device and board peripherals */
result = cybsp_init();
/* Board init failed. Stop program execution */
if (result != CY_RSLT_SUCCESS)
{
CY_ASSERT(0);
}
/* Enable global interrupts */
__enable_irq();
/* Initialize retarget-io to use the debug UART port */
result = cy_retarget_io_init_fc(CYBSP_DEBUG_UART_TX, CYBSP_DEBUG_UART_RX,
CYBSP_DEBUG_UART_CTS,CYBSP_DEBUG_UART_RTS,CY_RETARGET_IO_BAUDRATE);
/* retarget-io init failed. Stop program execution */
if (result != CY_RSLT_SUCCESS)
{
CY_ASSERT(0);
}
/* Initialize the User LED */
init_cycfg_pins();
result = cyhal_gpio_init(CYBSP_USER_LED, CYHAL_GPIO_DIR_OUTPUT,
CYHAL_GPIO_DRIVE_STRONG, CYBSP_LED_STATE_OFF);
/* GPIO init failed. Stop program execution */
if (result != CY_RSLT_SUCCESS)
{
CY_ASSERT(0);
}
/* \x1b[2J\x1b[;H - ANSI ESC sequence for clear screen */
printf("\x1b[2J\x1b[;H");
printf("****************** "
"HAL: Hello World! Example "
"****************** \r\n\n");
printf("Hello World!!!\r\n\n");
printf("For more projects, "
"visit our code examples repositories:\r\n\n");
printf("https://github.com/Infineon/"
"Code-Examples-for-ModusToolbox-Software\r\n\n");
/* Initialize timer to toggle the LED */
timer_init();
pwm_init();
printf("LED Breathing.\r\n");
while(1);
#if 0
for (;;)
{
/* Check if 'Enter' key was pressed */
if (cyhal_uart_getc(&cy_retarget_io_uart_obj, &uart_read_value, 1)
== CY_RSLT_SUCCESS)
{
if (uart_read_value == '\r')
{
/* Pause LED blinking by stopping the timer */
if (led_blink_active_flag)
{
cyhal_timer_stop(&led_blink_timer);
printf("LED blinking paused \r\n");
}
else /* Resume LED blinking by starting the timer */
{
cyhal_timer_start(&led_blink_timer);
printf("LED blinking resumed\r\n");
}
/* Move cursor to previous line */
printf("\x1b[1F");
led_blink_active_flag ^= 1;
}
}
/* Check if timer elapsed (interrupt fired) and toggle the LED */
if (timer_interrupt_flag)
{
/* Clear the flag */
timer_interrupt_flag = false;
/* Invert the USER LED state */
//cyhal_gpio_toggle(CYBSP_USER_LED);
}
}
#endif
}
/*******************************************************************************
* Function Name: isr_timer
********************************************************************************
* Summary:
* This is the interrupt handler function for the timer interrupt.
*
* Parameters:
* callback_arg Arguments passed to the interrupt callback
* event Timer/counter interrupt triggers
*
* Return:
* void
*******************************************************************************/
static void isr_timer1(void *callback_arg, cyhal_timer_event_t event)
{
(void) callback_arg;
(void) event;
/* Set the interrupt flag and process it from the main while(1) loop */
timer_interrupt_flag = true;
}
static void isr_timer(void* callback_arg, cyhal_timer_event_t event)
{
(void)callback_arg;
(void)event;
if(timer_count > 0)
timer_count -= 1;
if(timer_count == 0)
{
timer_count = 2000;
//cyhal_gpio_toggle(CYBSP_USER_LED1);
}
if(timer_count < 1000)
{
cyhal_pwm_set_duty_cycle(&pwm_led2_control,timer_count/10.0,10000);
}
else {
cyhal_pwm_set_duty_cycle(&pwm_led2_control, (2000-timer_count)/10.0,10000);
}
}
/*******************************************************************************
* Function Name: timer_init
********************************************************************************
* Summary:
* This function creates and configures a Timer object. The timer ticks
* continuously and produces a periodic interrupt on every terminal count
* event. The period is defined by the 'period' and 'compare_value' of the
* timer configuration structure 'led_blink_timer_cfg'. Without any changes,
* this application is designed to produce an interrupt every 1 second.
*
* Parameters:
* none
*
* Return :
* void
*
*******************************************************************************/
void timer_init(void)
{
cy_rslt_t result;
const cyhal_timer_cfg_t led_blink_timer_cfg =
{
.compare_value = 0, /* Timer compare value, not used */
.period = LED_BLINK_TIMER_PERIOD, /* Defines the timer period */
.direction = CYHAL_TIMER_DIR_UP, /* Timer counts up */
.is_compare = false, /* Don't use compare mode */
.is_continuous = true, /* Run timer indefinitely */
.value = 0 /* Initial value of counter */
};
/* Initialize the timer object. Does not use input pin ('pin' is NC) and
* does not use a pre-configured clock source ('clk' is NULL). */
result = cyhal_timer_init(&led_blink_timer, NC, NULL);
/* timer init failed. Stop program execution */
if (result != CY_RSLT_SUCCESS)
{
CY_ASSERT(0);
}
/* Configure timer period and operation mode such as count direction,
duration */
cyhal_timer_configure(&led_blink_timer, &led_blink_timer_cfg);
/* Set the frequency of timer's clock source */
cyhal_timer_set_frequency(&led_blink_timer, LED_BLINK_TIMER_CLOCK_HZ);
/* Assign the ISR to execute on timer interrupt */
cyhal_timer_register_callback(&led_blink_timer, isr_timer, NULL);
/* Set the event on which timer interrupt occurs and enable it */
cyhal_timer_enable_event(&led_blink_timer, CYHAL_TIMER_IRQ_TERMINAL_COUNT,
7, true);
/* Start the timer with the configured settings */
cyhal_timer_start(&led_blink_timer);
}
void pwm_init(void)
{
cyhal_pwm_init_cfg(&pwm_led2_control,&tcpwm_0_group_1_cnt_6_hal_config);
cyhal_pwm_start(&pwm_led2_control);
}
/* [] END OF FILE */
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