《DSP应用实例》PPT课件

方波发生器设计用TMS320VC5402实现方波发生器。假设时钟频率为4MHz,在XF端输出占空比为50%的方波，方波的周期由片上定时器确定,采用中断方法实现。,定时器初始化关闭定时器，TCR中的TSS=1；加载PRD。设定定时中断周期，每中断一次,输出端电平取反一次；启动定时器，初始化TDDR，TSS=0，TRB=1,中断初始化中断允许寄存器IFR中的定时中断位TINT=1,清除未处理完的定时中断；中断屏蔽寄存器IMR中的定时屏蔽位TINT=1,开放定时中断；状态控制寄存器ST1中的中断标志位INTM=0,开放全部中断。,周期为4ms的方波发生器，定时中断周期为2ms,每中断一次，输出端电平取一次反。初始化定时器0；根据定时长度计算公式：Tt=T*(TDDR+1)*(PRD+1)；给定TDDR=9，PRD=79，CLKOUT主频f=4MHz，T=250ns；Tt=250*(9+1)*(79+1)=2,000,000(ns)=2(ms),#include#include#include#include#include#defineIMR*(volatileunsignedint*)0 x00#defineIFR*(volatileunsignedint*)0 x01#defineST1*(volatileunsignedint*)0 x07#definePRD*(volatileunsignedint*)0 x25#defineTCR*(volatileunsignedint*)0 x26externintflag=0；当前XF输出电平标志，flag=1，则XF=1；否则，XF=0interruptvoidFB(void);,主程序代码,主程序代码,voidmain()TCR=TCR|0X0010;TSS=1，停止定时器0TIM=79;PRD=79;TCR=0X0269;启动定时器0IFR=IFR|0X0008;IFR中TINT=1，清除未处理完的定时中断IMR=IMR|0X0008;中断屏蔽寄存器IMR中定时屏蔽位TINT=1，开放定时中断ST1=ST1开放全部可屏蔽中断while(1)；等中断,中断服务程序代码,interruptvoidFB()中断服务程序if(flag=1)当前XF=1ST1=ST1,中断向量表文件vectors.asm,.sectvectors.ref_main在当前模块中使用但在其他段中定义的符号.ref_FBRESET:;resetvectorBD_main复位之后执行主程序NOPNOPnmi:RETE;enableinterruptsandreturnfromoneNOPNOPNOP;softwareinterruptssint17.space4*16sint18.space4*16sint19.space4*16sint20.space4*16sint21.space4*16sint22.space4*16sint23.space4*16,sint24.space4*16sint25.space4*16sint26.space4*16sint27.space4*16sint28.space4*16sint29.space4*16sint30.space4*16int0:RETE;Externaluserinterrupt#0NOPNOPNOPint1:RETE;Externaluserinterrupt#1NOPNOPNOP,中断向量表文件vectors.asm,int2:RETE;Externaluserinterrupt#2NOPNOPNOPtint:BD_FB;Timerinterrupt中断服务程序入口NOPNOPrint0:RETE;McBSP#0receiveinterrupt(default)NOPNOPNOPxint0:RETE;McBSP#0transmitinterrupt(default)NOPNOPNOPrint2:RETE;McBSP#2receiveinterrupt(default)NOPNOPNOP,中断向量表文件vectors.asm,xint2:RETE;McBSP#2transmitinterrupt(default)NOPNOPNOPint3:RETE;Externaluserinterrupt#3NOPNOPNOPhint:RETE;HPIinterruptNOPNOPNOPrint1:RETE;McBSP#1receiveinterrupt(default)NOPNOPNOPxint1:RETE;McBSP#1transmitinterrupt(default)NOPNOPNOP.space16*16.end,中断向量表文件vectors.asm,链接命令文件,MEMORYPAGE0:PROG:origin=0 x3000,len=0 x0f00VECT:origin=0 x3f00,len=0 x0080PAGE1:DATA:origin=