Microchip Technology dsPIC33F Family Manual de usuario descargar pdf (Pagina 8)

dsPIC33F Family Reference Manual

12.5.1 Code Example for Period Measurement

The following code example shows the time period measurement using the Input Capture

module. The capture event is generated on every rising edge and the capture interrupt is

generated after taking two time stamps for period measurement, as illustrated in Figure 12-5.

Example 12-1: Capture Code Example

// Initialize Capture Module

IC1CONbits.ICM=0b00; // Disable Input Capture 1 module

IC1CONbits.ICTMR= 1; // Select Timer2 as the IC1 Time base

IC1CONbits.ICI= 0b01; // Interrupt on every second capture event

IC1CONbits.ICM= 0b011; // Generate capture event on every Rising edge

// Enable Capture Interrupt And Timer2

IPC0bits.IC1IP = 1; // Setup IC1 interrupt priority level

IFS0bits.IC1IF = 0; // Clear IC1 Interrupt Status Flag

IEC0bits.IC1IE = 1; // Enable IC1 interrupt

// Capture Interrupt Service Routine

unsigned int timePeriod= 0;

void __attribute__((__interrupt__)) _IC1Interrupt(void)

{

unsigned int t1,t2;

t1=IC1BUF;

t2=IC1BUF;

IFS0bits.IC1IF=0;

if(t2>t1)

timePeriod = t2-t1;

else

timePeriod = (PR2 - t1) + t2;

}

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Microchip Technology dsPIC33F Family Manual de usuario Pagina 8