Cantafford
Member
Hello,
Using PIC18F2580 I'm trying to simply make a led flash every 1 second(on for one second, off for one second) using TIMER0.
I have done the following:
-set the TIMER0 as a 16bit counter
-used an initial frequency of 8MHz
-configured the preescaler to be 1:16
-obtained therefore a frequency of 0.5MHz which should by my calculation cause the timer0 to overflow every 500ms(approximately)
Here is the code & the schematic:
The header.h:
And schematic:
When I try running this code the led turns on and stays on, it never turns off(so it won't flash). Please help me correct this. Thank you for reading!
Using PIC18F2580 I'm trying to simply make a led flash every 1 second(on for one second, off for one second) using TIMER0.
I have done the following:
-set the TIMER0 as a 16bit counter
-used an initial frequency of 8MHz
-configured the preescaler to be 1:16
-obtained therefore a frequency of 0.5MHz which should by my calculation cause the timer0 to overflow every 500ms(approximately)
Here is the code & the schematic:
Code:
/*
* File: main.c
* Author: Paul
*
* Created on November 10, 2015, 7:48 PM
*/
#include <stdio.h>
#include <stdlib.h>
#include "header.h"
volatile int count = 0;
void init()
{
TMR0ON = 1;
T08BIT = 0; // timer0 is now a 16bit counter
PSA = 0; // preescaler assigned to tmr0 input
T0PS0 = 1; // preescaler is now...
T0PS1 = 1; // a...
T0PS2 = 0; // 1:16 preescaler(so 8:16 = 0.5 MHz)
GIE = 1; // enable global interupts
T0IE = 1; // enable timer 0 interupts
T0IF = 0; // clear timer 0's interrupt flag
}
void interrupt ISR()
{
if(T0IF == 1)
{
count++;
if(count==1)
{
LATCbits.LATC0 = !LATCbits.LATC0;
count = 0;
}
T0IF = 0;
}
}
void main()
{
OSCCON = 0x76; // freq is 8 MHz
TRISCbits.RC0 = 0; // led is here
init(); // initialize timer0
while(1); // loop forever
}The header.h:
Code:
// PIC18F2580 Configuration Bit Settings
// 'C' source line config statements
#include <xc.h>
// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.
// CONFIG1H
#pragma config OSC = IRCIO67 // Oscillator Selection bits (Internal oscillator block, port function on RA6 and RA7)
#pragma config FCMEN = OFF // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config IESO = OFF // Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)
// CONFIG2L
#pragma config PWRT = OFF // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = OFF // Brown-out Reset Enable bits (Brown-out Reset disabled in hardware and software)
#pragma config BORV = 3 // Brown-out Reset Voltage bits (VBOR set to 2.1V)
// CONFIG2H
#pragma config WDT = OFF // Watchdog Timer Enable bit (WDT disabled (control is placed on the SWDTEN bit))
#pragma config WDTPS = 32768 // Watchdog Timer Postscale Select bits (1:32768)
// CONFIG3H
#pragma config PBADEN = ON // PORTB A/D Enable bit (PORTB<4:0> pins are configured as analog input channels on Reset)
#pragma config LPT1OSC = OFF // Low-Power Timer 1 Oscillator Enable bit (Timer1 configured for higher power operation)
#pragma config MCLRE = OFF // MCLR Pin Enable bit (RE3 input pin enabled; MCLR disabled)
// CONFIG4L
#pragma config STVREN = ON // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
#pragma config LVP = ON // Single-Supply ICSP Enable bit (Single-Supply ICSP enabled)
#pragma config BBSIZ = 1024 // Boot Block Size Select bit (1K words (2K bytes) boot block)
#pragma config XINST = OFF // Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))
// CONFIG5L
#pragma config CP0 = OFF // Code Protection bit (Block 0 (000800-001FFFh) not code-protected)
#pragma config CP1 = OFF // Code Protection bit (Block 1 (002000-003FFFh) not code-protected)
#pragma config CP2 = OFF // Code Protection bit (Block 2 (004000-005FFFh) not code-protected)
#pragma config CP3 = OFF // Code Protection bit (Block 3 (006000-007FFFh) not code-protected)
// CONFIG5H
#pragma config CPB = OFF // Boot Block Code Protection bit (Boot block (000000-0007FFh) not code-protected)
#pragma config CPD = OFF // Data EEPROM Code Protection bit (Data EEPROM not code-protected)
// CONFIG6L
#pragma config WRT0 = OFF // Write Protection bit (Block 0 (000800-001FFFh) not write-protected)
#pragma config WRT1 = OFF // Write Protection bit (Block 1 (002000-003FFFh) not write-protected)
#pragma config WRT2 = OFF // Write Protection bit (Block 2 (004000-005FFFh) not write-protected)
#pragma config WRT3 = OFF // Write Protection bit (Block 3 (006000-007FFFh) not write-protected)
// CONFIG6H
#pragma config WRTC = OFF // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected)
#pragma config WRTB = OFF // Boot Block Write Protection bit (Boot block (000000-0007FFh) not write-protected)
#pragma config WRTD = OFF // Data EEPROM Write Protection bit (Data EEPROM not write-protected)
// CONFIG7L
#pragma config EBTR0 = OFF // Table Read Protection bit (Block 0 (000800-001FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR1 = OFF // Table Read Protection bit (Block 1 (002000-003FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR2 = OFF // Table Read Protection bit (Block 2 (004000-005FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR3 = OFF // Table Read Protection bit (Block 3 (006000-007FFFh) not protected from table reads executed in other blocks)
// CONFIG7H
#pragma config EBTRB = OFF // Boot Block Table Read Protection bit (Boot block (000000-0007FFh) not protected from table reads executed in other blocks)
#define _XTAL_FREQ 8000000And schematic:
When I try running this code the led turns on and stays on, it never turns off(so it won't flash). Please help me correct this. Thank you for reading!
