Interval Timer Problem

I think I have found a solution:

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double count_timeH_before=0;

double count_timeL_before=0;

double count_timeH_after=0;

double count_timeL_after=0;

double total_time_steps=0;

double calculated_frequency=0;

alt_u32 count_step_before=0x0;

alt_u32 count_step_after=0x0;

//start address of the counter

IOWR_ALTERA_AVALON_TIMER_PERIODH(SYS_CLK_TIMER_BASE,0xFFFF);

IOWR_ALTERA_AVALON_TIMER_PERIODL(SYS_CLK_TIMER_BASE,0xFFFF);

IOWR_ALTERA_AVALON_TIMER_CONTROL(SYS_CLK_TIMER_BASE,ALTERA_AVALON_TIMER_CONTROL_STOP_MSK);

//total_time is in seconds but is measured in ms

//the range depends on the frequency you want to have

//while((total_time<=10) & (total_time>=5)){ //while((total_time<=0.001) & (total_time>=0.00065)){

//by writing to the snapregister you get the data from the counter

IOWR_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE,0x1);

IOWR_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE,0x2);

//start the counter

IOWR_ALTERA_AVALON_TIMER_CONTROL(SYS_CLK_TIMER_BASE,0x06);

printf("Control : %x\n",IORD_ALTERA_AVALON_TIMER_CONTROL(SYS_CLK_TIMER_BASE));

printf("Status: %x\n", IORD_ALTERA_AVALON_TIMER_STATUS(SYS_CLK_TIMER_BASE));

count_timeL_before= IORD_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE);

printf("SnapL : %e\n", count_timeL_before);

count_timeH_before= IORD_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE);

printf("SnapH : %e\n", count_timeH_before);

count_step_before = IORD_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE)<<16;

count_step_before |=IORD_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE);

//wait till the FAD gives back the right frequency

int j;

for ( j = 0; j < 2; ++j) {

push_The_Button(FAD_CLOCK_BASE);

printf("Flanke Nummer %d \n", j);

}

//printf("SnapH : %e\n", (double)IORD_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE));

//stop the counter

IOWR_ALTERA_AVALON_TIMER_CONTROL(SYS_CLK_TIMER_BASE,0x8);

//by writing to the snapregister you get the data from the counter

IOWR_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE,0x1);

count_timeL_after= IORD_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE);

printf("SnapL : %x\n", IORD_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE));

count_timeH_after= IORD_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE);

printf("SnapH : %x\n", IORD_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE));

count_step_after = IORD_ALTERA_AVALON_TIMER_SNAPH(SYS_CLK_TIMER_BASE)<<16;

count_step_after =count_step_after|(IORD_ALTERA_AVALON_TIMER_SNAPL(SYS_CLK_TIMER_BASE));

total_time_steps= (count_step_before-count_step_after);

printf("Zwischenergebnis:%e\n", total_time_steps);

calculated_time= total_time_steps/(50000000);

printf("Calculated_time: %e\n",calculated_time);

calculated_frequency=1/calculated_time;

printf("Frequenz: %e\n",calculated_frequency);

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This should be right. Isn't it?