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1、实验三：定时器一、 实验原理1.定时器的结构2. 定时器中断周期3.实验功能：通过XF管脚控制LED闪动以一定规律进行闪烁。二、 硬件资源及在片外围电路硬件资源： DSP芯片、CPU、LED、蜂鸣器、电阻、电容等在片外围电路： 时钟发生器、定时器、通用输入/输出口等三、 参数设置CPU工作时钟： *clkmd =0x21b3; 0010000110110011 CLKOUT=18M中断频率： 9 /* PRSC 4bit*/ 18M/9000=2KHZ四、 实验流程图五、 程序#include #include #include #include #include extern void VE
2、CSTART(void);#define TIMER_CTRL TIMER_TCR_RMK( TIMER_TCR_IDLEEN_DEFAULT, /* IDLEEN = 0 */ TIMER_TCR_FUNC_OF(0), /* FUNC = 0 */ TIMER_TCR_TLB_RESET, /* TLB = 1 */ TIMER_TCR_SOFT_BRKPTNOW, /* SOFT = 0 */ TIMER_TCR_FREE_WITHSOFT, /* FREE = 0 */ TIMER_TCR_PWID_OF(0), /* PWID = 0 */ TIMER_TCR_ARB_RESET,
3、/* ARB = 1 */ TIMER_TCR_TSS_START, /* TSS = 0 */ TIMER_TCR_CP_PULSE, /* CP = 0 */ TIMER_TCR_POLAR_LOW, /* POLAR = 0 */ TIMER_TCR_DATOUT_0 /* DATOUT = 0 */ ) /* Create a TIMER configuration structure that can be passed */* to TIMER_config CSL function for initialization of Timer */* control registers
4、. */TIMER_Config timCfg0 = TIMER_CTRL, /* TCR0 */ 0x3400u, /* PRD0 0x3400=13312*/ 14400, /* PRD0 16bit 0x3400=144000=14400*10*/ 9 /* PRSC 4bit*/;/中断频率=Fcpu/(9000*1)=144MHz/13312=1kHzUint16 eventId0; /* Create a TIMER_Handle object for use with TIMER_open */TIMER_Handle mhTimer0;volatile Uint16 timer
5、0_cnt = 0;/* Function/ISR prototypes */interrupt void timer0Isr(void);int old_intm;Uint16 tim_val;Uint16 xfchange = 0;Uint16 ms,f;void main(void) /* Initialize CSL library - This is REQUIRED ! */ /*CLS库的初始化，这是必需的*/ CSL_init(); /* Set IVPH/IVPD to start of interrupt vector table */ /*修改寄存器IVPH，IVPD，重
6、新定义中断向量表*/ IRQ_setVecs(Uint32)(&VECSTART); /* Temporarily disable all maskable interrupts */*禁止所有可屏蔽的中断源*/old_intm = IRQ_globalDisable(); /* Open Timer 0, set registers to power on defaults */*打开定时器0，设置其为上电的的默认值，并返回其句柄*/mhTimer0 = TIMER_open(TIMER_DEV0, TIMER_OPEN_RESET);/* Get Event Id associated w
7、ith Timer 0, for use with */* CSL interrupt enable functions. */*获取定时器0的中断ID号*/ eventId0 = TIMER_getEventId(mhTimer0);/* Clear any pending Timer interrupts */*清除定时器0的中断状态位*/IRQ_clear(eventId0);/* Place interrupt service routine address at */* associated vector location */*为定时器0设置中断服务程序*/IRQ_plug(eve
8、ntId0,&timer0Isr);/* Write configuration structure values to Timer control regs */*设置定时器0的控制与周期寄存器*/ TIMER_config(mhTimer0, &timCfg0); /* Enable Timer interrupt */*使能定时器的中断*/IRQ_enable(eventId0); /* Enable all maskable interrupts */*设置寄存器ST1的INTM位，使能所有的中断*/IRQ_globalEnable(); /* Start Timer */*启动定时器
9、0*/TIMER_start(mhTimer0);ms=0;for(;)/ Wait for at least 10 timer periods /等待10个定时周期if(xfchange = 0) /点亮XF的LED CHIP_FSET(ST1_55,XF,1); else/关掉XF的LED CHIP_FSET(ST1_55,XF,0); /* Restore old value of INTM */*恢复INTM旧的值*/IRQ_globalRestore(old_intm);/* We are through with timer, so close it */*关掉定时器0*/TIMER_close(mhTimer0); /*定时器0的中断程序*/interrupt void timer0Isr(void) ms+; +timer0_cnt; if(timer0_cnt = 500) xfchange = 1; if(timer0_cnt = 1000) timer0_cnt = 0; xfchange = 0;
