timer.c (16F877A-Showtime)

//chen thu vien
#include"main.h"
void _InitTimer0(void)
{
    //OPTION_REG
    T0CS=0; //chon che do TIMER
    PSA=0; //dinh bo ti le cho TIMER
    PS2=PS1=PS0=0; //chon ti le 1:2
    TMR0IE=1; //cho phep ngat TIMER0
    GIE=1; //cho phep ngat toan cuc
}
void _SETUP_TIMER_0(char source_signal,char prescaler)
{
    switch(source_signal)
    {
        case INTERNAL:
        {
            T0CS=0; //chon che do TIMER
            PSA=0; //dinh bo ti le cho TIMER
            break;
        }
        case EXTERNAL:
        {
            T0CS=1; //chon che do COUNTER
            PSA=1; //dinh bo ti le cho COUNTER
            break;
        }
        default: //khi co dieu kien nao duoc thoa man
            break;
    }
    switch(prescaler)
    {
        case DIV2:
        {
            //chon ti le 1:2
            PS2=0;
            PS1=0;
            PS0=0;
            break;
        }
        case DIV4:
        {
            //chon ti le 1:4
            PS2=0;
            PS1=0;
            PS0=1;
            break;
        }
        case DIV8:
        {
            //chon ti le 1:8
            PS2=0;
            PS1=1;
            PS0=0;
            break;
        }
        case DIV16:
        {
            //chon ti le 1:16
            PS2=0;
            PS1=1;
            PS0=1;
            break;
        }
        case DIV32:
        {
            //chon ti le 1:32
            PS2=1;
            PS1=0;
            PS0=0;
            break;
        }
        case DIV64:
        {
            //chon ti le 1:64
            PS2=1;
            PS1=0;
            PS0=1;
            break;
        }
        case DIV128:
        {
            //chon ti le 1:128
            PS2=1;
            PS1=1;
            PS0=0;
            break;
        }
        case DIV256:
        {
            //chon ti le 1:256
            PS2=1;
            PS1=1;
            PS0=1;
            break;
        }
        default: //khi khong co dieu kien nao duoc thoa man
            break;
    }
}
void _SET_TIMER0(unsigned char value)
{
    TMR0=value; //ghi gia tri vao thanh ghi TIMER0
}