/******************************************************************************
 * @file     LDROM_main.c
 * @version  V1.00
 * $Revision: 2 $
 * $Date: 16/10/25 4:29p $
 * @brief    Show how to reboot to LDROM functions from APROM.
 *           This sample code set VECMAP to LDROM and reset to re-boot to LDROM.
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 * @copyright Copyright (C) 2016 Nuvoton Technology Corp. All rights reserved.
*****************************************************************************/
#include <stdio.h>
#include "NUC126.h"

#define PLL_CLOCK       72000000

void SYS_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/

    /* Enable Internal RC 22.1184MHz clock */
    CLK_EnableXtalRC(CLK_PWRCTL_HIRCEN_Msk);

    /* Waiting for Internal RC clock ready */
    CLK_WaitClockReady(CLK_STATUS_HIRCSTB_Msk);

    /* Switch HCLK clock source to Internal RC and HCLK source divide 1 */
    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_HIRC, CLK_CLKDIV0_HCLK(1));

    /* Enable external XTAL 12MHz clock */
    CLK_EnableXtalRC(CLK_PWRCTL_HXTEN_Msk);

    /* Waiting for external XTAL clock ready */
    CLK_WaitClockReady(CLK_STATUS_HXTSTB_Msk);

    /* Set core clock as PLL_CLOCK from PLL */
    CLK_SetCoreClock(PLL_CLOCK);

    /* Enable UART module clock */
    CLK_EnableModuleClock(UART0_MODULE);

    /* Select UART module clock source */
    CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UARTSEL_HXT, CLK_CLKDIV0_UART(1));

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set PD multi-function pins for UART0 RXD and TXD */
    SYS->GPD_MFPL &= ~(SYS_GPD_MFPL_PD0MFP_Msk | SYS_GPD_MFPL_PD1MFP_Msk);
    SYS->GPD_MFPL |= (SYS_GPD_MFPL_PD0MFP_UART0_RXD | SYS_GPD_MFPL_PD1MFP_UART0_TXD);
}

void UART_Init()
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    UART_Open(UART0, 115200);
}

int main()
{
    uint32_t u32TimeOutCnt;

    /* Unlock protected register */
    SYS_UnlockReg();

    SYS_Init();
    UART_Init();

    printf("\n\n");
    printf("FMC IAP Sample Code [LDROM code]\n");

    /* Enable FMC ISP function */
    FMC_Open();

    printf("\n\nPress any key to branch to APROM...\n");
    getchar();

    printf("\n\nChange VECMAP and branch to LDROM...\n");
    u32TimeOutCnt = SystemCoreClock; /* 1 second time-out */
    UART_WAIT_TX_EMPTY(UART0)
        if(--u32TimeOutCnt == 0) break;

    /* Mask all interrupt before changing VECMAP to avoid wrong interrupt handler fetched */
    __set_PRIMASK(1);

    /* Change VECMAP for booting to APROM */
    FMC_SetVectorPageAddr(FMC_APROM_BASE);

    /* Lock protected Register */
    SYS_LockReg();

    /* Software reset to boot to APROM */
    NVIC_SystemReset();

    while(1);
}

/*** (C) COPYRIGHT 2016 Nuvoton Technology Corp. ***/
