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標題: C8051F410單片機利用pca捕獲外部脈沖 [打印本頁]

作者: y電子設計dsd 時間: 2019-7-31 14:16
標題: C8051F410單片機利用pca捕獲外部脈沖
//-----------------------------------------------------------------------------
// 聲明：外部引腳的脈沖輸入CEX0為P0^0，
//-----------------------------------------------------------------------------

#include <c8051f410.h>                // SFR declarations
#include"UART.h"
#include <stdio.h>

#define SYSCLK    24500000          // SYSCLK frequency in Hz
#define BAUDRATE       9600          // Baud rate of UART in bps

sfr16 PCA0CP0 = 0xFB;                // PCA0 Compare Register Definition
unsigned int CLKNUM = 0;
float period;

void OSCILLATOR_Init (void);
void PORT_Init (void);
void PCA0_Init (void);
static unsigned int capture_period;
unsigned int counter;
void main (void)
{
PCA0MD = 0x00;                   // Disable watchdog timer

PORT_Init ();                      // Initialize crossbar and GPIO
OSCILLATOR_Init ();                // Initialize oscillator
PCA0_Init ();                      // Initialize PCA0
UART0_Init ();

EA = 1;

while (1)
{
   printf("CLKNUM= %d us\n",CLKNUM);
      printf("period= %f us\n",period);
}
}

void OSCILLATOR_Init (void)
{
OSCICN = 0x87;                   // Set internal oscillator to run
                                    // at its maximum frequency

CLKSEL = 0x00;                   // Select the internal osc. as
                                    // the SYSCLK source
   RSTSRC = 0x04;                   // enable missing clock detector(串口需要)
}

void PORT_Init (void)
{
XBR0 = 0x01;                   //串口通信使能
XBR1 = 0x41;                   // Route CEX0 to P0.0,
                                    // Enable crossbar and weak pull-ups
}

void PCA0_Init (void)
{
PCA0CN = 0x00;                   // Stop counter; clear all flags
PCA0MD = 0x08;                   // Use 系統時鐘 as time base
PCA0CPM0 = 0x21;                   // Module 0 = Rising Edge Capture Mode
                                    // enable CCF flag.
EIE1 = 0x10;                      // Enable PCA interrupts
CR = 1;                            // Start PCA counter
}
void PCA0_ISR (void) interrupt 11
{
static unsigned int current_capture_value, previous_capture_value;

if (CCF0)                                                                      // If Module 0 caused the interrupt
{
//       CLKNUM++;

   CCF0 = 0;                                                                   // Clear module 0 interrupt flag.
   current_capture_value = PCA0CP0;                                              // Store most recent capture value
   capture_period = current_capture_value - previous_capture_value;             // Calculate capture period from last two values.
   previous_capture_value = current_capture_value;                               // Update previous capture value with most recent info.
         period = capture_period *4.0816326530612244897959183673469e-8;




   }
else                               // Interrupt was caused by other bits.
{
   PCA0CN &= ~0x86;                // Clear other interrupt flags for PCA
}
}

作者: lyl_420819 時間: 2019-11-16 17:01
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