/**************************************************************************//**
 * @file     main.c
 * @version  V1.00
 * $Revision: 3 $
 * $Date: 15/02/06 10:22a $
 * @brief    Change duty cycle and period of output waveform by PWM Double Buffer function.
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 *
 * @copyright Copyright (C) 2014 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "M058S.h"

/*---------------------------------------------------------------------------------------------------------*/
/* Macro, type and constant definitions                                                                    */
/*---------------------------------------------------------------------------------------------------------*/

#define PLLCON_SETTING      CLK_PLLCON_50MHz_HXT
#define PLL_CLOCK           50000000


/*---------------------------------------------------------------------------------------------------------*/
/* Global variables                                                                                        */
/*---------------------------------------------------------------------------------------------------------*/

/**
 * @brief       PWMA IRQ Handler
 *
 * @param       None
 *
 * @return      None
 *
 * @details     ISR to handle PWMA interrupt event
 */
void PWMA_IRQHandler(void)
{
    static int toggle = 0;

    /* Update PWMA channel 0 period and duty */
    if(toggle == 0)
    {
        PWMA->CNR0 = 99;
        PWMA->CMR0 = 39;
    }
    else
    {
        PWMA->CNR0 = 199;
        PWMA->CMR0 = 99;
    }
    toggle ^= 1;
    /* Clear channel 0 period interrupt flag */
    PWMA->PIIR |= PWM_PIIR_PWMIF0_Msk;
}

void SYS_Init(void)
{
	uint32_t u32TimeOutCnt;
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/

    /* Enable Internal RC clock */
    CLK->PWRCON |= CLK_PWRCON_OSC22M_EN_Msk;

    /* Waiting for IRC22M clock ready */
    u32TimeOutCnt = __HIRC;
	while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_OSC22M_STB_Msk))
		if(--u32TimeOutCnt == 0) break;

    /* Switch HCLK clock source to Internal RC and HCLK source divide 1 */
    CLK->CLKSEL0 &= ~CLK_CLKSEL0_HCLK_S_Msk;
    CLK->CLKSEL0 |= CLK_CLKSEL0_HCLK_S_HIRC;
    CLK->CLKDIV &= ~CLK_CLKDIV_HCLK_N_Msk;

    /* Set PLL to power down mode and PLL_STB bit in CLKSTATUS register will be cleared by hardware.*/
    CLK->PLLCON |= CLK_PLLCON_PD_Msk;

    /* Enable external 12MHz XTAL, internal 22.1184MHz */
    CLK->PWRCON |= CLK_PWRCON_XTL12M_EN_Msk | CLK_PWRCON_OSC22M_EN_Msk;

    /* Enable PLL and Set PLL frequency */
    CLK->PLLCON = PLLCON_SETTING;

    /* Waiting for clock ready */
    while(!(CLK->CLKSTATUS & (CLK_CLKSTATUS_PLL_STB_Msk | CLK_CLKSTATUS_XTL12M_STB_Msk | CLK_CLKSTATUS_OSC22M_STB_Msk)));

    /* Switch HCLK clock source to PLL, STCLK to HCLK/2 */
    CLK->CLKSEL0 = CLK_CLKSEL0_STCLK_S_HCLK_DIV2 | CLK_CLKSEL0_HCLK_S_PLL;

    /* Enable IP clock */
    CLK->APBCLK = CLK_APBCLK_UART0_EN_Msk | CLK_APBCLK_PWM01_EN_Msk | CLK_APBCLK_PWM23_EN_Msk;

    /* IP clock source */
    CLK->CLKSEL1 = CLK_CLKSEL1_UART_S_PLL;

    /* IP clock source */
    CLK->CLKSEL1 |= CLK_CLKSEL1_PWM01_S_HXT | CLK_CLKSEL1_PWM23_S_HXT;

    /* Reset PWMA channel0~channel3 */
    SYS->IPRSTC2 = SYS_IPRSTC2_PWM03_RST_Msk;
    SYS->IPRSTC2 = 0;

    /* Update System Core Clock */
    SystemCoreClockUpdate();

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set P3 multi-function pins for UART RXD and TXD */
    SYS->P3_MFP &= ~(SYS_MFP_P30_Msk | SYS_MFP_P31_Msk);
    SYS->P3_MFP |= (SYS_MFP_P30_RXD | SYS_MFP_P31_TXD);
    /* Set P2 multi-function pins for PWMA Channel0~3 */
    SYS->P2_MFP &= ~(SYS_MFP_P20_Msk | SYS_MFP_P21_Msk | SYS_MFP_P22_Msk | SYS_MFP_P23_Msk);
    SYS->P2_MFP |= (SYS_MFP_P20_PWM0 | SYS_MFP_P21_PWM1 | SYS_MFP_P22_PWM2 | SYS_MFP_P23_PWM3);
}

void UART0_Init(void)
{

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    UART0->BAUD = UART_BAUD_MODE2 | UART_BAUD_MODE2_DIVIDER(PLL_CLOCK, 115200);
    UART0->LCR = UART_WORD_LEN_8 | UART_PARITY_NONE | UART_STOP_BIT_1;
}

/*---------------------------------------------------------------------------------------------------------*/
/*  Main Function                                                                                          */
/*---------------------------------------------------------------------------------------------------------*/
int32_t main(void)
{
    /* Init System, IP clock and multi-function I/O
       In the end of SYS_Init() will issue SYS_LockReg()
       to lock protected register. If user want to write
       protected register, please issue SYS_UnlockReg()
       to unlock protected register if necessary */

    /* Unlock protected registers */
    SYS_UnlockReg();

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

    /* Lock protected registers */
    SYS_LockReg();

    /* Init UART to 115200-8n1 for print message */
    UART0_Init();
    printf("+------------------------------------------------------------------------+\n");
    printf("|                          PWM Driver Sample Code                        |\n");
    printf("|                                                                        |\n");
    printf("+------------------------------------------------------------------------+\n");
    printf("  This sample code will use PWMA channel 0 to output waveform\n");
    printf("  I/O configuration:\n");
    printf("    waveform output pin: PWM0(P2.0)\n");
    printf("\nUse double buffer feature.\n");

    /*
        PWMA channel 0 waveform of this sample shown below:

        |<-        CNR + 1  clk     ->|  CNR + 1 = 199 + 1 CLKs
                       |<-CMR+1 clk ->|  CMR + 1 = 99 + 1 CLKs
                                      |<-   CNR + 1  ->|  CNR + 1 = 99 + 1 CLKs
                                               |<CMR+1>|  CMR + 1 = 39 + 1 CLKs
      __                ______________          _______
        |______100_____|     100      |____60__|   40  |_____PWM waveform


    */

    /* Set channel 0 prescaler to 2. Actual value fill into register needs to minus 1. */
    PWMA->PPR = (PWMA->PPR & ~(PWM_PPR_CP01_Msk)) | (1 << PWM_PPR_CP01_Pos);

    /* Set channel 0 clock divider to 1 */
    PWMA->CSR = (PWMA->CSR & ~(PWM_CSR_CSR0_Msk)) | (PWM_CLK_DIV_1 << PWM_CSR_CSR0_Pos);

    /* Enable PWMA channel 0 auto-reload mode */
    PWMA->PCR |= PWM_PCR_CH0MOD_Msk;
    /*
      Configure PWMA channel 0 init period and duty.
      Period is __HXT / (prescaler * clock divider * (CNR + 1))
      Duty ratio = (CMR + 1) / (CNR + 1)
      Period = 12 MHz / (2 * 1 * (199 + 1)) =  30000 Hz
      Duty ratio = (99 + 1) / (199 + 1) = 50%
    */
    PWMA->CMR0 = 99;
    PWMA->CNR0 = 199;

    /* Enable PWMA channel 0 output */
    PWMA->POE |= PWM_POE_PWM0_Msk;

    /* Enable PWMA channel 0 period interrupt */
    PWMA->PIER = PWM_PIER_PWMIE0_Msk;
    NVIC_EnableIRQ(PWMA_IRQn);

    /* Start */
    PWMA->PCR |= PWM_PCR_CH0EN_Msk;

    while(1);

}
