定时器应用实例.doc

最近写了个小程序，动态数码管扫描，算是定时器的应用吧，单片机上经常看得到，我移植过来了，充实一下内容吧。 ????? 首先在SOPC中添加一个定时器，两个8位的PIO，一个用于数据线，一个是作为开关，作为开关的可以根据数码管个数决定PIO的数量。 ????? 编译完以后就可以写程序了，程序如下所示，利用的是动态余辉效果 /* * ============================================================== * * Filename: main.c * * Description: * * Version: 1.0.0 * Created: 2010.6.17 * Revision: none * Compiler: Nios II 9.0 IDE * * Author: 马瑞 (AVIC) * Email: avic633@ * * ============================================================== */ #include stdio.h #include sys/unistd.h #include io.h #include string.h #include system.h #include altera_avalon_pio_regs.h #include altera_avalon_timer_regs.h #include alt_types.h #include sys/alt_irq.h unsigned char segtab[10]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; //0~9 unsigned char led_buffer[8]={0}; unsigned char bittab[8]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f}; static unsigned char cnt=0; static void timer_init(void); /* * === FUNCTION =================================================== * Name: main * Description: * ==================================================================== */ int main(void) { unsigned char i=0,j=0; unsigned char buf[20]; timer_init(); while(1){ sprintf(buf,%08u,j++); for(i=0;i8;i++){ led_buffer[i] = buf[7-i]-0; } usleep(500000); } return 0; } /* * === FUNCTION =================================================== * Name: timer_irq * Description: 定时器中断函数 * ================================================================= */ static void timer_irq(void *context, alt_u32 id) { IOWR_ALTERA_AVALON_PIO_DATA(SEG_SEL_BASE, 0xff); IOWR_ALTERA_AVALON_PIO_DATA(SEG_SEL_BASE, bittab[cnt]); IOWR_ALTERA_AVALON_PIO_DATA(SEG_DAT_BASE, segtab[led_buffer[cnt]]); cnt++; if(cnt==8) cnt=0; IOWR_ALTERA_AVALON_TIMER_STATUS(TI