/**************************************************************************//**
 * @file     main.c
 * @version  V3.00
 * $Revision: 4 $
 * $Date: 16/10/17 2:04p $
 * @brief    Implement CRC in CRC-CCITT mode and get the CRC checksum result.
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 * @copyright Copyright (C) 2016 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "M0564.h"


#define PLLCTL_SETTING  CLK_PLLCTL_72MHz_HXT
#define PLL_CLOCK       72000000


void SYS_Init(void)
{
	uint32_t u32TimeOutCnt;

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Enable HIRC clock */
    CLK->PWRCTL |= CLK_PWRCTL_HIRCEN_Msk;

    /* Waiting for HIRC clock ready */
    u32TimeOutCnt = __HIRC;
    while(!(CLK->STATUS & CLK_STATUS_HIRCSTB_Msk))
		if(--u32TimeOutCnt == 0) break;

    /* Switch HCLK clock source to HIRC */
    CLK->CLKSEL0 = CLK_CLKSEL0_HCLKSEL_HIRC;

    /* Set PLL to Power-down mode and PLLSTB bit in CLK_STATUS register will be cleared by hardware.*/
    CLK->PLLCTL |= CLK_PLLCTL_PD_Msk;

    /* Enable HXT */
    CLK->PWRCTL |= CLK_PWRCTL_HXTEN_Msk;

    /* Enable PLL and Set PLL frequency */
    CLK->PLLCTL = PLLCTL_SETTING;

    /* Waiting for clock ready */
    u32TimeOutCnt = __HIRC;
    while(!(CLK->STATUS & CLK_STATUS_PLLSTB_Msk))
		if(--u32TimeOutCnt == 0) break;

    u32TimeOutCnt = __HIRC;
    while(!(CLK->STATUS & CLK_STATUS_HXTSTB_Msk))
		if(--u32TimeOutCnt == 0) break;

    /* Switch STCLK source to HCLK/2 and HCLK clock source to PLL */
    CLK->CLKSEL0 = CLK_CLKSEL0_STCLKSEL_HCLK_DIV2 | CLK_CLKSEL0_HCLKSEL_PLL;

    /* Enable peripheral clock */
    CLK->APBCLK0 = CLK_APBCLK0_UART0CKEN_Msk;

    /* Peripheral clock source */
    CLK->CLKSEL1 = CLK_CLKSEL1_UARTSEL_PLL;

    /* Update System Core Clock */
    /* User can use SystemCoreClockUpdate() to calculate PllClock, SystemCoreClock and CycylesPerUs automatically. */
    SystemCoreClockUpdate();

    /*---------------------------------------------------------------------------------------------------------*/
    /* 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 UART0_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Reset UART module */
    SYS->IPRST1 |=  SYS_IPRST1_UART0RST_Msk;
    SYS->IPRST1 &= ~SYS_IPRST1_UART0RST_Msk;

    /* Configure UART0 and set UART0 Baudrate */
    UART0->BAUD = UART_BAUD_MODE2 | UART_BAUD_MODE2_DIVIDER(PllClock, 115200);
    UART0->LINE = UART_WORD_LEN_8 | UART_PARITY_NONE | UART_STOP_BIT_1;
}

/*---------------------------------------------------------------------------------------------------------*/
/*  MAIN function                                                                                          */
/*---------------------------------------------------------------------------------------------------------*/
int main(void)
{
    const uint8_t acCRCSrcPattern[] = {0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38};
    uint32_t i, u32TargetChecksum = 0xA12B, u32CalChecksum = 0;
    uint16_t *p16SrcAddr;

    /* Unlock protected registers */
    SYS_UnlockReg();

    /* Init System, peripheral clock and multi-function I/O */
    SYS_Init();

    /* Lock protected registers */
    SYS_LockReg();

    /* Init UART0 for printf */
    UART0_Init();

    printf("\n\nCPU @ %d Hz\n", SystemCoreClock);
    printf("+---------------------------------------------+\n");
    printf("|    CRC-CCITT Polynomial Mode Sample Code    |\n");
    printf("+---------------------------------------------+\n\n");

    printf("# Calculate [0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38] CRC-CCITT checksum value.\n");
    printf("    - Seed value is 0xFFFF             \n");
    printf("    - CPU write data length is 16-bit \n");
    printf("    - Checksum complement disable    \n");
    printf("    - Checksum reverse disable       \n");
    printf("    - Write data complement disable  \n");
    printf("    - Write data reverse disable     \n");
    printf("    - Checksum should be 0x%X        \n\n", u32TargetChecksum);

    /* Enable CRC controller clock */
    CLK->AHBCLK |= CLK_AHBCLK_CRCCKEN_Msk;

    /* Disable CRC function */
    CRC->CTL &= ~CRC_CTL_CRCEN_Msk;

    /* Configure CRC controller for CRC-CCITT CPU mode */
    CRC_SET_SEED(0xFFFF);
    CRC->CTL = CRC_CCITT | CRC_CPU_WDATA_16 | CRC_CTL_CRCEN_Msk;

    /* Reset CRC checksum */
    CRC->CTL |= CRC_CTL_CHKSINIT_Msk;

    /* Convert 16-bit source data */
    p16SrcAddr = (uint16_t *)acCRCSrcPattern;

    /* Start to execute CRC-CCITT operation */
    for(i = 0; i < sizeof(acCRCSrcPattern) / 2; i++)
    {
        CRC_WRITE_DATA((p16SrcAddr[i] & 0xFFFF));
    }

    /* Disable CRC function */
    CRC->CTL &= ~CRC_CTL_CRCEN_Msk;

    /* Get CRC-CCITT checksum value */
    u32CalChecksum = (CRC->CHECKSUM & 0xFFFF);
    printf("CRC checksum is 0x%X ... %s.\n", u32CalChecksum, (u32CalChecksum == u32TargetChecksum) ? "PASS" : "FAIL");

    while(1);
}

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