MSP430教程10：MSP430單片機(jī)WDT看門狗定時(shí)器

1、看門狗定時(shí)器用來(lái)防止程序因供電電源、空間電磁干擾或其它原因引起的強(qiáng)烈干擾噪聲而跑飛的事故。程序中設(shè)置看門狗清零指令 WDTCTL=WDTPW+WDTCNTCL，當(dāng)程序跑飛不能及時(shí)清零看門狗，導(dǎo)致看門狗溢出復(fù)位，這樣程序可以恢復(fù)正常運(yùn)行狀態(tài)。 一、WDT寄存器包括WDTCNT和WDTCTL，兩個(gè)寄存器在上電和系統(tǒng)復(fù)位內(nèi)容全部清零 1.記數(shù)單元WDTCNT：WDTCNT是16位增記數(shù)器，由MSP430選定的時(shí)鐘電路產(chǎn)生的固定周期脈沖信號(hào)對(duì)記數(shù)器進(jìn)行加法記數(shù)。WDTCNT不能直接軟件存取，必須通過(guò)看門狗定時(shí)器的控制寄存器WDTCTL來(lái)控制。 2.控制寄存器WDTCTL：WDTCTL由兩部分組成，高8

2、位用作口令，即5AH(頭文件中定義為WDTPW)，低8位是對(duì)WDT操作的控制命令。寫入WDT控制命令時(shí)先寫入口令WDTPW，口令寫錯(cuò)將導(dǎo)致系統(tǒng)復(fù)位。讀WDTCTL時(shí)不需口令，低字節(jié)WDTCTL的值，高字節(jié)讀出始終為69H。   bit     15-8         7          6     

3、60;    5           4           3            2             1&

4、#160;           0           口令      HOLD    NMIES     NMI      TMSEL    CNT

5、CL     SSEL      IS1         IS0 IS1 SI0   選擇看門狗定時(shí)器的定時(shí)輸出，T為WDTCNT的輸入時(shí)鐘源周期。 TMSEL WDT工作模式選擇   0    0     T*2的15次方      &#

6、160;                                                 &#

7、160;                         0      看門狗模式   0    1     T*2的13次方     &#

8、160;                                                 &#

9、160;                          1      定時(shí)器模式   1    0     T*2的9次方    

10、60;                                                 

11、60;                       NMI    選擇RST/NMI引腳功能     1    1     T*2的6次方       

12、0;                                                 

13、0;                          0      RST/NMI為復(fù)位端 SSEL     選擇WDTCNT的時(shí)鐘源        

14、0;                                                 

15、0;      1      RST/NMI為非屏蔽中斷輸入    0         SMCLK                        &#

16、160;                 1         ACLK NMIES   選擇NMI中斷的邊沿觸發(fā)方式                   

17、60;                                    HOLD   停止看門狗定時(shí)器工作    0      

18、60;  上升沿觸發(fā)NMI中斷                                              

19、0;                         0       看門狗功能激活    1         下降沿觸發(fā)NMI中斷     

20、;                                                  

21、;                 1       時(shí)鐘禁止輸入，記數(shù)停止 二、WDT的操作 1.用戶通過(guò)設(shè)置WDTCTL中的TMSEL和HOLD控制位使WDT工作在看門狗模式、定時(shí)器模式和低功耗模式三種模式。 a.看門狗模式 (TMSEL=0 ,HOLD=0)   如果記數(shù)時(shí)間到，就會(huì)產(chǎn)生復(fù)位和激活系統(tǒng)上電清除信號(hào)，系統(tǒng)從上電復(fù)位的地址重啟動(dòng)&#

22、160;      中斷向量為RESET_VECTOR b.定時(shí)器模式(TMSEL=1，HOLD=0)   這一模式產(chǎn)生選定時(shí)間的周期性中斷 中斷標(biāo)志位為WDTIFG  中斷向量為 WDT_VECTOR c.低功耗模式(TMSEL=X，HOLD=1)   WDTCTL=WDTPW+WDTHOLD; 2.WDT通過(guò)SSEL 和IS0 IS1 3位可以確定與8種時(shí)鐘源相關(guān)的時(shí)間（ACLK=32768Hz，SMCLK=1MHz）    WDT_MDLY_32&#

23、160;                                         WDT_MRST_32    WDT_MDLY_8  

24、60;                                         WDT_MRST_8    WDT_MDLY_0_5  

25、60;                                     WDT_MRST_0_5        WDT_MDLY_0_064  

26、;                                   WDT_MRST_0_064       WDT_ADLY_1000      

27、0;                                WDT_ARST_1000    WDT_ADLY_250            

28、                             WDT_ARST_250    WDT_ADLY_16               

29、0;                          WDT_ARST_16    WDT_ADLY_1_9                 

30、60;                      WDT_ARST_1_9 三、看門狗應(yīng)用       使用看門狗定時(shí)器產(chǎn)生一個(gè)方波（周期性取反P1.0） #include "msp430x201x.h" void main(void)   WDT=WDT_MDLY_32; &#

31、160; IE1 |=WDTIE;   P1DIR |=0x01;   _EINT();   for(;)            _BIS_SR(CPUOFF);         _NOP();    interruptWDT_VECTOR void watchdog_timer(void)    P1OUT

32、=0x01; / MSP430x5xx/ -/ /| XIN|-/ | | XOUT|-/ -|RST |/ | P1.7|->S1/ | P1.0|->LED#include <msp430f5529.h>/函數(shù)聲明void timerA0_ini(void);void timerA1_ini(void);void clk_set(void);void S1_ini(void);unsigned int flag = 0;unsigned int flagFREQ = 3;unsigned int CCR0 = 100;unsigned int step = 1;un

33、signed int step_default = 1;void main(void)WDTCTL = WDTPW + WDTHOLD; / Stop WDTclk_set();P1DIR |= BIT2; / P1.2 outputP1DIR |= BIT3+BIT4+BIT5;P1OUT &= 0xC7;P1SEL |= BIT2;timerA0_ini();timerA1_ini();S1_ini();_EINT();while(1);#pragma vector=TIMER1_A0_VECTOR_interrupt void TIMER1_A0_ISR(void)if (fla

34、g = 0)TA0CCR1 += step;if (TA0CCR1 >= TA0CCR0)flag = 1;else if (flag = 1)TA0CCR1 -= step;if (TA0CCR1 <= 0)flag = 0;/* *Name:PORT1_ISR *description :PORT1中斷服務(wù)函數(shù)，按鍵S1按下時(shí)在P1.7 *description 產(chǎn)生中斷，此時(shí)更新CCR0值，實(shí)現(xiàn)更改LED *description 閃爍頻率的增減 *input:延時(shí)時(shí)間(ms) *output:N/A */# pragma vector=PORT1_VECTOR_interr

35、upt void PORT1_ISR(void)_delay_cycles(1000);if ( P1IFG & BIT7 )if(flagFREQ>=5)flagFREQ=1;elseflagFREQ+;TA1CCR0 = 32768/(200/flagFREQ);P1OUT = (P1OUT&0xC7) | flagFREQ<<3;/_EINT();P1IFG &= BIT7;void timerA1_ini(void)/timerA初始化TA1CCR0 = 546;TA1CTL = TASSEL_ACLK + MC_UP + TACLR ;TA1

36、CCTL0 = CCIE;void timerA0_ini(void)/timerA初始化TA0CCR0 = 100;TA0CCR1 = 0;TA0CTL = TASSEL_SMCLK + MC_UP + TACLR ;TA0CCTL1 = OUTMOD_3;/* *Name:S1_ini *description :S1開(kāi)關(guān)管腳中斷初始化 *input:N/A *output:N/A */void S1_ini(void)P1REN |= BIT7; / 使能P1.7端口電阻P1OUT |= BIT7; / 設(shè)置P1.7端口電阻為上拉（如果該位置低，則設(shè)置成下拉電路）P1IES |= BIT

37、7; /選擇觸發(fā)邊沿，下降沿觸發(fā)volatileP1IE |= BIT7; /打開(kāi)P1.7的中斷P1IFG &= 0x00; /清零中斷標(biāo)志位void clk_set(void)P5SEL |= BIT2+BIT3; / Port select XT2UCSCTL6 &= XT2OFF; / Enable XT2UCSCTL3 |= SELREF_2; / FLLref = REFO/ Since LFXT1 is not used,/ sourcing FLL with LFXT1 can cause/ XT1OFFG flag to setUCSCTL4 |= SELA_2

38、; / ACLK=REFO,SMCLK=DCO,MCLK=DCO/ Loop until XT1,XT2 & DCO stabilizes - in this case loop until XT2 settlesdoUCSCTL7 &= (XT2OFFG + XT1LFOFFG + DCOFFG);/ Clear XT2,XT1,DCO fault flagsSFRIFG1 &= OFIFG; / Clear fault flagswhile (SFRIFG1&OFIFG); / Test oscillator fault flagUCSCTL6 &=

39、 XT2DRIVE0; / Decrease XT2 Drive according to/ expected frequencyUCSCTL4 |= SELS_5 + SELM_5; / SMCLK=MCLK=XT2UCSCTL6 = (UCSCTL6 & DIVS_0) | DIVS_4;/* * main.c */#include "msp430f5529.h"void S1_ini(void);void main(void) WDTCTL = WDTPW + WDTHOLD;P1DIR |= BIT0;S1_ini();_EINT();while(1);vo

40、id S1_ini(void)P1REN |= BIT7; / 使能P1.7端口電阻P1OUT |= BIT7; / 設(shè)置P1.7端口電阻為上拉（如果該位置低，則設(shè)置成下拉電路）P1IES |= BIT7; /選擇觸發(fā)邊沿，下降沿觸發(fā)P1IE |= BIT7; /打開(kāi)P1.7的中斷P1IFG &= BIT7; /清零中斷標(biāo)志位# pragma vector=PORT1_VECTOR_interrupt void PORT1_ISR(void)_delay_cycles(1000);if ( P1IFG & BIT7 )P1OUT = BIT0;P1IFG &= BIT7

41、;/*/ MSP430 Blink the LED Demo - Software Toggle P1.0/ Description; Toggle P1.0 by xor'ing P1.0 inside of a software loop./ ACLK = n/a, MCLK = SMCLK = default DCO/ MSP430x5xx/ -/ /| XIN|-/ | | |/ -|RST XOUT|-/ | |/ | P1.0|->LED/ J. Stevenson/ Texas Instruments, Inc/ July 2011/ Built with Code Composer Studio v5/*#include <msp430.h>int main(void)WDTCTL = WDTPW + WDTHO