What does the period in the timer exactly specify?

Hello Badr

A code post to what you are doing and when you see the variable in watch window would be useful

Regards

Amit

Hello Amit,

The next code should test running two timers (T0A & T0B) in parallel in split mode.

each timer blink a led with a ratio (1:5) of frequency.

#include <stdint.h>
#include <stdbool.h>
#include "inc/tm4c1294ncpdt.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/sysctl.h"
#include "driverlib/interrupt.h"
#include "driverlib/gpio.h"
#include "driverlib/timer.h"
//////////////////////////////////////////////////////////////////////////
int counta = 0;
int countb = 0;
int clock = 0;
int compa = clock * 5
int main(void)
{
	uint32_t ui32Period;
	uint32_t ui32SysClkFreq;

	//SET SYSTEM CLK
	ui32SysClkFreq = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);
	clock = SysCtlClockGet();
	//ENABLE PERIPHERALS
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);

	//CONFIGURE PERIPHERALS
	GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE,GPIO_PIN_1 | GPIO_PIN_0);
	TimerConfigure(TIMER0_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_PERIODIC | TIMER_CFG_B_PERIODIC);
	//TimerConfigure(TIMER1_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_PERIODIC);

	//SET THE PERIOD OF THE TIMER
	ui32Period = clock;
	TimerLoadSet(TIMER0_BASE, TIMER_B, ui32Period -1);
	TimerLoadSet(TIMER0_BASE, TIMER_A, clock -1);

	//ENABLE INTERRUPTS
	IntEnable(INT_TIMER0A);
	TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
	IntEnable(INT_TIMER0B);
	TimerIntEnable(TIMER0_BASE, TIMER_TIMB_TIMEOUT);
	IntMasterEnable();

	//ENABLE TIMERS
	TimerEnable(TIMER0_BASE, TIMER_A);
	TimerEnable(TIMER0_BASE, TIMER_B);
	

	while(1)
	{
	}

}
//ISR
void Timer0AIntHandler(void)
{
	// Clear the timer interrupt flag
	TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
	counta++;

	if (counta==9155)
	{
		if(GPIOPinRead(GPIO_PORTN_BASE,GPIO_PIN_1))
			GPIOPinWrite(GPIO_PORTN_BASE,GPIO_PIN_1,0x0);
		else
			GPIOPinWrite(GPIO_PORTN_BASE,GPIO_PIN_1,0x2);
		counta = 0;
	}
}
void Timer0BIntHandler(void)
{
	// Clear the timer interrupt flag
	TimerIntClear(TIMER0_BASE, TIMER_TIMB_TIMEOUT);
	countb++;

	if (countb==45776)
	{
		if(GPIOPinRead(GPIO_PORTN_BASE,GPIO_PIN_0))
			GPIOPinWrite(GPIO_PORTN_BASE,GPIO_PIN_0,0x0);
		else
			GPIOPinWrite(GPIO_PORTN_BASE,GPIO_PIN_0,0x1);
		countb = 0;
	}
}

So, from configuration, I calculated from the clock freq (=120MHz) the time of full count for the timers and counted the appropriate time to make it count 5:1 seconds.

Now when I try to add clock variable to expressions tab to watch its value, it shows to me another value than expected.

Further more, I cant understand what is the function of "period" in TimerLoadSet() function ?

Regards,

Badr.

Thanks Amit,

I know it's possible to do it with 32-bit timer Iam doing it on 16-bit on purpose that I want to try the both of timers A & B in the same time in the split mode , even so, it's similar to using any width of timers because Iam counting the overflows or the time-outs of the timer so, the no, of (time-outs * the single time-out in sec) gives me either 1sec or 5 seconds as I wish.

Any way I figured out what's wrong which is that I firstly didn't understand what period is but, as soon as I put the right value in it (2^16-1), It worked thanks to God .

Regards,

Badr.