main.c

/******************************************************************************
* File Name:   main.c
*
* Description: This is the source code for the XMC MCU: GPIO Toggle Example
*              for ModusToolbox.
*
* Related Document: See README.md
*
******************************************************************************
*
* Copyright (c) 2015-2021, Infineon Technologies AG
* All rights reserved.                        
*                                             
* Boost Software License - Version 1.0 - August 17th, 2003
* 
* Permission is hereby granted, free of charge, to any person or organization
* obtaining a copy of the software and accompanying documentation covered by
* this license (the "Software") to use, reproduce, display, distribute,
* execute, and transmit the Software, and to prepare derivative works of the
* Software, and to permit third-parties to whom the Software is furnished to
* do so, all subject to the following:
* 
* The copyright notices in the Software and this entire statement, including
* the above license grant, this restriction and the following disclaimer,
* must be included in all copies of the Software, in whole or in part, and
* all derivative works of the Software, unless such copies or derivative
* works are solely in the form of machine-executable object code generated by
* a source language processor.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
* SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
* FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*                                                                              
*****************************************************************************/

#include "cybsp.h"
#include "cy_utils.h"

/*******************************************************************************
* Macros
*******************************************************************************/

/* SysTick timer frequency in Hz  */
#define TICKS_PER_SECOND            1000

/* USER LED toggle period in milliseconds */
#define USER_LED_TOGGLE_PERIOD_MS   1000

/*******************************************************************************
* Global Variables
*******************************************************************************/

/* Variable for keeping track of time */
static volatile uint32_t ticks = 0;

/*******************************************************************************
* Function Name: SysTick_Handler
********************************************************************************
* Summary:
* This is the interrupt handler function for the SysTick timer interrupt.
* It counts the time elapsed in milliseconds since the timer started. 
*
* Parameters:
*  none
*
* Return:
*  none
*
*******************************************************************************/
void SysTick_Handler(void)
{
    ticks++;
}

/*******************************************************************************
* Function Name: sys_now
********************************************************************************
* Summary:
* Returns the current time in milliseconds.
*
* Parameters:
*  none
*
* Return:
*  the current time in milliseconds
*
*******************************************************************************/
__STATIC_INLINE uint32_t sys_now(void)
{
    return ticks;
}

/*******************************************************************************
* 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 elapsed time
* and toggles an LED at 1Hz to create an LED blinky. 
*
* Parameters:
*  none
*
* Return:
*  int
*
*******************************************************************************/

int main(void)
{
    cy_rslt_t result;

    /* Initialize the device and board peripherals */
    result = cybsp_init();
    if (result != CY_RSLT_SUCCESS)
    {
        CY_ASSERT(0);
    }

    /* System timer configuration */
    SysTick_Config(SystemCoreClock / TICKS_PER_SECOND);

    while (1)
    {
        uint32_t start = sys_now();

        /* Wait till 'USER_LED_TOGGLE_PERIOD_MS' milliseconds are elapsed 
           since the start of the loop */
        while ((sys_now() - start) < USER_LED_TOGGLE_PERIOD_MS);

        /* Toggle the USER LED state */
        XMC_GPIO_ToggleOutput(CYBSP_USER_LED_PORT, CYBSP_USER_LED_PIN);
    }
}

/* [] END OF FILE */