Tiva C edge timing mode - arm

Question

Hello i have been coding with Tm4c123gh6pm lately and i have faced a part where i want to use the edge timing mode , now i haven't went for the tivaware api's i just went for traditional register level and following the datasheet and i faced this problem
i want to know which pin to use as the one where the timer is waiting for the rising edge to come so it moves the current timer value ?
i checked the data sheet all i can find is that timer 0 is somehow related to PB6 and PF0 now i tried PB6 and it didn't work but is that even the correct approach ?
are these the correct pins the microcontroller's timer waits for the rising edge to move the current timer value ?
here is a sample of my code and please note that this is just a testing code im trying its not a final code what i did was copy the initialization section in the datasheet for the timer mode i want and followed it step by step
this code will make the counter start running from 0xFF downwards but when i place a 'high' signal i.e 3.3 volts on PB6 nothing is moved to the GPTMTnR register.
i just wonder if there is something im doing wrong and im not noticing ?
#include "tm4c123gh6pm.h"
void Timer0Init(void);
int main(void)
{
int i=0;
Timer0Init();
while(1){
for(i=0;i<100000;i++){
}
}
return 0;
}
void Timer0Init(void)
{
//initialize PORT B
volatile unsigned long delay;
SYSCTL_RCGC2_R |= 0x00000002; // 1) B clock
delay = SYSCTL_RCGC2_R; // delay to allow clock to stabilize
GPIO_PORTB_AMSEL_R &= 0x00; // 2) disable analog function
GPIO_PORTB_PCTL_R &= 0x00000000; // 3) GPIO clear bit PCTL
GPIO_PORTB_DIR_R &= 0x00; // 4.2) PB all input
GPIO_PORTB_AFSEL_R &= 0x40; // 5) no alternate function
GPIO_PORTB_DEN_R |= 0xFF; // 7) enable digital pins PF4-PF1
GPIO_PORTB_PCTL_R = 7;
//timer clock
SYSCTL_RCGCTIMER_R |=0x01;
delay = SYSCTL_RCGCTIMER_R;
//1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes.
TIMER0_CTL_R &= 0xFE;
//2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x0000.0004.
TIMER0_CFG_R= 0x00000004;
//3. In the GPTM Timer Mode (GPTMTnMR) register, write the TnCMR field to 0x1 and the TnMR field to 0x3.
TIMER0_TAMR_R= TIMER0_TAMR_R | 0x007;
//4. Configure the type of event that the timer captures by writing the TnEVENT field of the GPTM Control (GPTMCTL) register.
TIMER0_CTL_R = TIMER0_CTL_R & 0xFFFFFFF3;
//5. If a prescaler is to be used, write the prescale value to the GPTM Timer n Prescale Register (GPTMTnPR).
//no prescaler for now
//6. Load the timer start value into the GPTM Timer n Interval Load (GPTMTnILR) register.
TIMER0_TAILR_R = 0xFF;
//7. If interrupts are required, set the CnEIM bit in the GPTM Interrupt Mask (GPTMIMR) register.
//no interrupts required
//8. Set the TnEN bit in the GPTM Control (GPTMCTL) register to enable the timer and start counting.
TIMER0_CTL_R= TIMER0_CTL_R & 0x00000001;
TIMER0_CTL_R |= 0x01;
//9. Poll the CnERIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases,
//the status flags are cleared by writing a 1 to the CnECINT bit of the GPTM Interrupt Clear (GPTMICR) register.
//The time at which the event happened can be obtained by reading the GPTM Timer n (GPTMTnR) register.
/*In Input Edge Timing mode, the timer continues running after an edge event has been detected,
but the timer interval can be changed at any time by writing the GPTMTnILR register. The change
takes effect at the next cycle after the write.*/
}

Answer 1

there was a problem with my portb initialization i used tivaware for that part and it worked perfectly fine now on placing high on PB6 it passes the current timer value to the other register
also note that when counting up the timer counts up to the value initialized in the TAIL_R register also if u want to reset the timer you need to write the value u want the timer to begin with in the TAV_R register
Best Of Luck everyone