Part Number: TM4C1294NCPDT
Hello
i am trying to calculate frequency of an input signal with timer capture mode.
however it running good but sometime the result get 0 value .
how could this happen ?
how eliminate this error?
#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_ints.h"
#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include "driverlib/gpio.h"
#include "driverlib/fpu.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/systick.h"
#include "driverlib/timer.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"
void calc_freq(void)
;
volatile uint32_t g_ui32Counter = 0;
uint32_t ui32SysClock=0, time=0, start=0,end=0;
bool flag=false;
void
SysTickIntHandler(void)
{
//
// Update the Systick interrupt counter.
//
if(g_ui32Counter>10000000){
g_ui32Counter=0;}
g_ui32Counter++;
}
void
InitConsole(void)
{
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
GPIOPinConfigure(GPIO_PA0_U0RX);
GPIOPinConfigure(GPIO_PA1_U0TX);
SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);
GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
UARTStdioConfig(0, 115200, 16000000);
}
void edge_capture(void)
{
TimerIntClear(TIMER1_BASE, TIMER_CAPB_EVENT);
if (flag==false){
start = TimerValueGet(TIMER1_BASE, TIMER_B);
flag=true;
}
else if (flag==true){
end=TimerValueGet(TIMER1_BASE, TIMER_B);
time=end-start;
flag=false;
TimerLoadSet(TIMER1_BASE, TIMER_B,(10000-1));
}
}
void Configure_timer(void)
{
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER1);
GPIOPinTypeTimer(GPIO_PORTD_BASE, GPIO_PIN_3);
GPIOPinConfigure(GPIO_PD3_T1CCP1);
TimerConfigure(TIMER1_BASE,(TIMER_CFG_SPLIT_PAIR | TIMER_CFG_B_CAP_TIME_UP));
TimerControlEvent(TIMER1_BASE,TIMER_B,TIMER_EVENT_POS_EDGE);
TimerPrescaleSet(TIMER1_BASE, TIMER_B, (120-1));
TimerLoadSet(TIMER1_BASE, TIMER_B,(10000-1));
IntRegister(INT_TIMER1B, edge_capture);
TimerIntClear(TIMER1_BASE, TIMER_CAPB_EVENT);
TimerIntEnable(TIMER1_BASE, TIMER_CAPB_EVENT);
IntEnable(INT_TIMER1B);
TimerEnable(TIMER1_BASE, TIMER_B);
}
int main(void)
{
FPULazyStackingEnable();
ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
SYSCTL_OSC_MAIN |
SYSCTL_USE_PLL|SYSCTL_CFG_VCO_480), 120000000);
InitConsole();
Configure_timer();
SysTickPeriodSet(ui32SysClock/1000000);
IntMasterEnable();
SysTickIntEnable();
SysTickEnable();
while(1)
{
if(time!=0)
{
calc_freq();
}
}
}
void calc_freq(void)
{
float y;
y=time/1200 ;
y=1/y;
time=100000*y;
UARTprintf("start :%d\n",time);
time=0;
end=0;
start=0;
}
