main.c

《嵌入式开发实例》全书所附源代码

unsigned long dummy = 0;

static unsigned long sw_wait_loop(volatile unsigned long ctr)
{
    while(ctr-- ) dummy++;
    return(dummy);
}



main() {
    while (1) {
        // toggle DSP_XF pin off and on, pausing long enough to make LED blink
        asm("      SSBX	xf");
        asm("      nop");
        asm("      nop");
        (void)sw_wait_loop(0xC0000);
        asm("      RSBX	xf");
        asm("      nop");
        asm("      nop");
        (void)sw_wait_loop(0xC0000);
    }
}