Timer trouble

Sorry Amit,
I just adjusted ui32Period = (SysCtlClockGet()/40);
In my thought, Timer period = 2Mhz. that mean. timer will count from zero to a value = 2,000,000. with frequency = SysCtlClockGet().
Am I right? If not please correct it.
Thanks!

Below program used to toggle RED LED with period = 2 second. Can you explain for me?

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include "inc/hw_memmap.h"
#include "driverlib/interrupt.h"
#include "driverlib/gpio.h"
#include "driverlib/sysctl.h"
#include "inc/hw_types.h"
#include "inc/hw_ints.h"
#include "inc/hw_gpio.h"
#include "driverlib/timer.h"

#define SW1 GPIO_PIN_4
#define SW2 GPIO_PIN_0

#define LED_RED GPIO_PIN_1
#define LED_GREEN GPIO_PIN_2
#define LED_BLUE GPIO_PIN_3


uint32_t readStatus,ui32Period,tinh;
uint32_t val=0;
int tick;

void INIT_LED()
{
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);
GPIOPinWrite(GPIO_PORTF_BASE, LED_RED|LED_GREEN|LED_BLUE, 0);
}

void config_timer()
{
SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC_UP);
ui32Period = (SysCtlClockGet()/40);//1s
TimerLoadSet(TIMER0_BASE, TIMER_A, ui32Period-1);//1s
TimerEnable(TIMER0_BASE, TIMER_A);
}
int main(void) {
SysCtlClockSet(SYSCTL_SYSDIV_2_5| SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

INIT_LED();
config_timer();

tinh = LED_RED;
while(1)
{
val=TimerValueGet(TIMER0_BASE,TIMER_A);
if(val==0)
{
GPIOPinWrite(GPIO_PORTF_BASE, LED_RED, tinh);
tinh = valLED ^ LED_RED;
}
}
}

Thanks

Hi,

Anh Nguyen Duc said:

I faced with trouble about frequency of timer as a counter mode

This is a little bit confusing what you really want to do.

But, supposing you try just to play with a timer, then I suggest to change the operating mode to counting down, as you test the timer value against zero - this is specific to counting down. To count up, you need to use the matching register, and when the timer value equals the content of matching register, then an event will be triggered. You load the timer register with a value and counting up no event is triggered - the timer overflows and then it gets zero value. 

Second, this kind of working is much better suited to work with interrupts, rather than polling the end value. 

Please review the user manual....

Hi,
In my case, zero mean a value within period, we can change it to whatever value, it's will blink red LED with period = 2 second (1s ON, 1s OFF).
As you can see, this line:
ui32Period = (SysCtlClockGet()/40);
I set period = 2,000,000; CPU frequency = 80Mhz, how it can blink with period = 2 second? I'm really confusing.

Anh Nguyen Duc said:

I still waiting for a answer

My small tech firm find that vendor's Rep provided "above/beyond" tech support.

Rather than "waiting" might several re-reads of the MCU manual's Timer section and the various Timer API examples - guide you to that critical answer?

It's likely that you'll require such Timer mastery to pursue your 64x32 RGB Led project - is it not?

Sometimes (perhaps often) individual study and experimentation proves superior to "waiting."