main.c

/******************************************************************************
* File Name:   main.c
*
* Description: This is the source code for the XMC MCU: UART DMA Example
*              for ModusToolbox. This example demonstrates how to stream data
*              using DMA via a Universal Serial Interface Channel (USIC)
*              based UART to external terminal.
*
* Related Document: See README.md
*
******************************************************************************
*
* Copyright (c) 2015-2024, 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"
#include "cy_retarget_io.h"
#include <stdio.h>

/*******************************************************************************
* Macros
*******************************************************************************/
/* Define macro to enable/disable printing of debug messages */
#define ENABLE_XMC_DEBUG_PRINT                  (0)

/* Size of source buffer(s) for the DMA to read from */
#if ENABLE_XMC_DEBUG_PRINT
#define BUFFER_LENGTH                           26
#else
#define BUFFER_LENGTH                           256
#endif

/* Preemptive priority value (starting from 0) of NVIC CPU Subsystem */
#define DEBUG_GPDMA_RECEIVE_EVENT_PRIORITY      63

/* Subpriority value (starting from 0) of NVIC CPU Subsystem */
#define DEBUG_GPDMA_RECEIVE_EVENT_SUB_PRIORITY  0

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

/* Source buffers for DMA */
uint8_t buffer1[BUFFER_LENGTH];
uint8_t buffer2[BUFFER_LENGTH];

/* Destination address pointer*/
uint32_t * dst_ptr = (uint32_t *) & (CYBSP_DEBUG_UART_HW->TBUF[0]);

/* Flag variable to register when transfer is finished */
volatile bool transfer_done = false;

/*******************************************************************************
 * Function Name: custom_delay
 ********************************************************************************
 * Summary:
 * This function sets custom delay for easier printing data on Serial Terminal
 *
 * Parameters:
 *  delay_cyc - Number of NOP commands
 *
 * Return:
 *  void
 *
 *******************************************************************************/
void custom_delay(int32_t delay_cyc)
{
    while (delay_cyc--)
        asm("NOP");
}

/*******************************************************************************
* Function Name: GPDMA0_INTERRUPT_HANDLER
********************************************************************************
* Summary:
* Interrupt handler called when transfer has completed
*
* Parameters:
*  void
*
* Return:
*  void
*
*******************************************************************************/
void GPDMA0_INTERRUPT_HANDLER(void)
{
    /* Set global variable to register event and notify main-loop */
    transfer_done = true;

    /* Clear event status */
    XMC_DMA_CH_ClearEventStatus(DMA_HW, DMA_NUM, XMC_DMA_CH_EVENT_BLOCK_TRANSFER_COMPLETE);
}

/*******************************************************************************
* Function Name: main
********************************************************************************
* Summary:
* This is the main function. It initializes the UART interface and configures
* DMA for streaming via UART.
* Waits for the transfer to finish and finally idles inside main-loop.
*
* Parameters:
*  void
*
* 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);
    }

    /* Initialize printf retarget */
    cy_retarget_io_init(CYBSP_DEBUG_UART_HW);

    #if ENABLE_XMC_DEBUG_PRINT
        printf("Initialization done\r\n");
    #endif

    /* Prepare source buffers with ASCII-codes A..Z and a..z */
    for (uint32_t i = 0; i < BUFFER_LENGTH; ++i)
    {
        buffer1[i] = i%26 + 'A';
        buffer2[i] = i%26 + 'a';
    }

    /* Event/interrupt configuration */
    NVIC_SetPriority(GPDMA0_0_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), DEBUG_GPDMA_RECEIVE_EVENT_PRIORITY, DEBUG_GPDMA_RECEIVE_EVENT_SUB_PRIORITY));
    NVIC_EnableIRQ(GPDMA0_0_IRQn);

    /* Initial trigger for DMA transfer */
    XMC_USIC_CH_TriggerServiceRequest(CYBSP_DEBUG_UART_HW, 0);
    #if ENABLE_XMC_DEBUG_PRINT
        printf("A USIC interrupt service request triggered\r\n");
        custom_delay(200000);
    #endif

    transfer_done = false;
    /* Set Block size of the next transfer */
    XMC_DMA_CH_SetBlockSize(DMA_HW, DMA_NUM, BUFFER_LENGTH);
    /* Set Source address of the next transfer */
    XMC_DMA_CH_SetSourceAddress(DMA_HW, DMA_NUM, (uint32_t)&buffer1[0]);
    /* Start transfer */
    XMC_DMA_CH_Enable(DMA_HW, DMA_NUM);

    /* Wait for completion of DMA transfer */
    while (transfer_done == false)
    {

    }

    #if ENABLE_XMC_DEBUG_PRINT
        printf("DMA transfer of buffer 1 completed\r\n");
        custom_delay(200000);
    #endif

    /* Execute DMA transfer of buffer 2 */
    transfer_done = false;
    /* Set Block size of the next transfer */
    XMC_DMA_CH_SetBlockSize(DMA_HW, DMA_NUM, BUFFER_LENGTH);
    /* Set Source address of the next transfer */
    XMC_DMA_CH_SetSourceAddress(DMA_HW, DMA_NUM, (uint32_t)&buffer2[0]);
    /* Start transfer */
    XMC_DMA_CH_Enable(DMA_HW, DMA_NUM);

    /* Wait for completion of DMA transfer */
    while (transfer_done == false)
    {

    }

    #if ENABLE_XMC_DEBUG_PRINT
        printf("DMA transfer of buffer 2 completed\r\n");
        custom_delay(200000);
    #endif

    while(1);
}

/* [] END OF FILE */