mini51通过PWM控制直流风扇

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/******************************************************************************

 * [url=home.php?mod=space&uid=288409]@file[/url]     main.c

 * [url=home.php?mod=space&uid=895143]@version[/url]  V1.00

 * $Revision: 3 $

 * $Date: 13/10/07 3:54p $ 

 * [url=home.php?mod=space&uid=247401]@brief[/url]    PWM sample for Mini51 series MCU

 *

 * @note

 * Copyright (C) 2013 Nuvoton Technology Corp. All rights reserved.

*****************************************************************************/  

#include <stdio.h>

#include "Mini51Series.h"









void SYS_Init(void)

{

/*---------------------------------------------------------------------------------------------------------*/

/* Init System Clock                                                                                       */

/*---------------------------------------------------------------------------------------------------------*/



    /* Unlock protected registers */

    while(SYS->RegLockAddr != 1) {

        SYS->RegLockAddr = 0x59;

        SYS->RegLockAddr = 0x16;

        SYS->RegLockAddr = 0x88;

    }



    /* Enable external 12MHz XTAL, internal 22.1184MHz */

    CLK->PWRCON = CLK_PWRCON_IRC22M_EN_Msk;



    /* Waiting for clock ready */

    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_IRC22M_STB_Msk));



    /* Enable IP clock */

    CLK->APBCLK = CLK_APBCLK_UART_EN_Msk | CLK_APBCLK_PWM23_EN_Msk;



    /* Update System Core Clock */

    /* User can use SystemCoreClockUpdate() to calculate SystemCoreClock and CycylesPerUs automatically. */

    SystemCoreClockUpdate();





/*---------------------------------------------------------------------------------------------------------*/

/* Init I/O Multi-function                                                                                 */

/*---------------------------------------------------------------------------------------------------------*/

    /* Set P1 multi-function pins for UART RXD, TXD */

    SYS->P0_MFP = SYS_MFP_P00_TXD | SYS_MFP_P01_RXD;



    /* Set P2 multi-function pins for PWM Channel */

    SYS->P2_MFP = SYS_MFP_P24_PWM2;





    /* Lock protected registers */

    SYS->RegLockAddr = 0;

}



void UART_Init(void)

{

    // Set UART to 8 bit character length, 1 stop bit, and no parity 

    UART->LCR = UART_LCR_WLS_Msk;        

    // 22.1184 MHz reference clock input, for 115200 bps

    // 22118400 / 115200 = 192. Using mode 2 to calculate baudrate, 192 - 2 = 190 = 0xBE

    UART->BAUD = UART_BAUD_DIV_X_EN_Msk | UART_BAUD_DIV_X_ONE_Msk | (0xBE);          

}



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 */

    SYS_Init(); 



    /* Init UART to 115200-8n1 for print message */

    UART_Init();



    printf("\nThis sample code will output PWM channel 0 to output waveform\n"); 

    printf("using double buffer feature.\n");

        

    /* 

        PWM channel 0 wave form of this sample showns 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 perscaler to 2. Actual value fill into register needs to minus 1.

    PWM->PPR = 0x0100;

    // Set channel 0 clock divider to 1

    PWM->CSR = PWM_CLK_DIV_1 << PWM_CSR_CSR2_Pos;

    // Enable PWM channel 0 auto-reload mode

    PWM->PCR = PWM_PCR_CH2MOD_Msk;

    /* 

      Configure PWM channel 1 init period and duty. 

      Period is HCLK / (perscaler * clock divider * (CNR + 1))

      Duty ratio = (CMR + 1) / (CNR + 1)

      Period = 22.1184 MHz / (1 * 1 * (1B9 + 1)) =  25000 Hz

      Duty ratio = (99 + 1) / (199 + 1) = 50%

    */

    PWM->CMR[2] = 0xB9;

    PWM->CNR[2] = 0x1B9;   



    

    // Enable PWM channel 2 output

    PWM->POE = PWM_POE_PWM2_Msk;

    

    // Start

    PWM->PCR |= PWM_PCR_CH2EN_Msk;

    

    while(1);



}



/*** (C) COPYRIGHT 2013 Nuvoton Technology Corp. ***/

PWM在控制上用的非常广泛的

其实难点就是怎么配置使用这个外设额

准备总结一下，封装成两个函数。一个配置，一个使用。

今晚认真学习PWM。

感觉都是寄存器的操作，有点头疼。。