/*
 * Copyright (c) 2015, Freescale Semiconductor, Inc.
 * Copyright 2016-2019 NXP
 * All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include "pin_mux.h"
#include "clock_config.h"
#include "board.h"
#include "fsl_lpuart.h"

/*******************************************************************************
 * Definitions
 ******************************************************************************/
#define DEMO_LPUART            LPUART0
#define DEMO_LPUART_CLKSRC     kCLOCK_ScgSircAsyncDiv3Clk
#define DEMO_LPUART_CLK_FREQ   CLOCK_GetFreq(kCLOCK_ScgSircAsyncDiv3Clk)
#define DEMO_LPUART_IRQn       LPUART0_IRQn
#define DEMO_LPUART_IRQHandler LPUART0_IRQHandler

/*! @brief Ring buffer size (Unit: Byte). */
#define DEMO_RING_BUFFER_SIZE 16

/*! @brief Ring buffer to save received data. */

/*******************************************************************************
 * Prototypes
 ******************************************************************************/

/*******************************************************************************
 * Variables
 ******************************************************************************/

uint8_t g_tipString[] =
    "Lpuart functional API interrupt example\r\nBoard receives characters then sends them out\r\nNow please input:\r\n";

/*
  Ring buffer for data input and output, in this example, input data are saved
  to ring buffer in IRQ handler. The main function polls the ring buffer status,
  if there are new data, then send them out.
  Ring buffer full: (((rxIndex + 1) % DEMO_RING_BUFFER_SIZE) == txIndex)
  Ring buffer empty: (rxIndex == txIndex)
*/
uint8_t demoRingBuffer[DEMO_RING_BUFFER_SIZE];
volatile uint16_t txIndex; /* Index of the data to send out. */
volatile uint16_t rxIndex; /* Index of the memory to save new arrived data. */

/*******************************************************************************
 * Code
 ******************************************************************************/

void DEMO_LPUART_IRQHandler(void)
{
    uint8_t data;
    uint16_t tmprxIndex = rxIndex;
    uint16_t tmptxIndex = txIndex;

    /* If new data arrived. */
    if ((kLPUART_RxDataRegFullFlag)&LPUART_GetStatusFlags(DEMO_LPUART))
    {
        data = LPUART_ReadByte(DEMO_LPUART);

        /* If ring buffer is not full, add data to ring buffer. */
        if (((tmprxIndex + 1) % DEMO_RING_BUFFER_SIZE) != tmptxIndex)
        {
            demoRingBuffer[rxIndex] = data;
            rxIndex++;
            rxIndex %= DEMO_RING_BUFFER_SIZE;
        }
    }
    SDK_ISR_EXIT_BARRIER;
}

/*!
 * @brief Main function
 */
int main(void)
{
    lpuart_config_t config;
    uint16_t tmprxIndex = rxIndex;
    uint16_t tmptxIndex = txIndex;

    BOARD_InitPins();
    BOARD_BootClockRUN();
    CLOCK_SetIpSrc(kCLOCK_Lpuart0, kCLOCK_IpSrcSircAsync);

    /*
     * config.baudRate_Bps = 115200U;
     * config.parityMode = kLPUART_ParityDisabled;
     * config.stopBitCount = kLPUART_OneStopBit;
     * config.txFifoWatermark = 0;
     * config.rxFifoWatermark = 0;
     * config.enableTx = false;
     * config.enableRx = false;
     */
    LPUART_GetDefaultConfig(&config);
    config.baudRate_Bps = BOARD_DEBUG_UART_BAUDRATE;
    config.enableTx     = true;
    config.enableRx     = true;

    LPUART_Init(DEMO_LPUART, &config, DEMO_LPUART_CLK_FREQ);

    /* Send g_tipString out. */
    LPUART_WriteBlocking(DEMO_LPUART, g_tipString, sizeof(g_tipString) / sizeof(g_tipString[0]));

    /* Enable RX interrupt. */
    LPUART_EnableInterrupts(DEMO_LPUART, kLPUART_RxDataRegFullInterruptEnable);
    EnableIRQ(DEMO_LPUART_IRQn);

    while (1)
    {
        /* Send data only when LPUART TX register is empty and ring buffer has data to send out. */
        while (kLPUART_TxDataRegEmptyFlag & LPUART_GetStatusFlags(DEMO_LPUART))
        {
            tmprxIndex = rxIndex;
            tmptxIndex = txIndex;
            if (tmprxIndex != tmptxIndex)
            {
                LPUART_WriteByte(DEMO_LPUART, demoRingBuffer[txIndex]);
                txIndex++;
                txIndex %= DEMO_RING_BUFFER_SIZE;
            }
        }
    }
}
