[PIC] Multiplexing 4x7segements Display and DS18b20 Correct timers

#include <16f84a.h>

#USE DELAY( CLOCK=4000000 ) /* Using a 4 Mhz clock */

#FUSES XT,NOWDT,NOPROTECT,NOPUT
/* Use XT mode, No Watch Dog, No Code Protect, No Power-up Timer */

#byte port_b=6 /* define the location of register port_b */
#byte port_a=5 /* define the location of register port_b */
#byte timer0low = 0xfd6
byte CONST LED_MAP[12] = {0x24,0xe7,0x4c,0x45,0x87,0x15,0x14,0x67,0x04,0x05,0xfb,0xdf};
byte CONST LED_POSITION[4] = {0x04,0x02,0x01,0x08};
unsigned int minus, less_than_one, single_number, tens;
/*
 * One wire (1-wire) driver for CCS C compiler. Suitable for use with devices
 * such as the DS18B20 1-wire digital temperature sensor.
 */
float value = 0.0;
float temp;
#define ONE_WIRE_PIN PIN_A4

/*
 * onewire_reset()
 * Description: Initiates the one wire bus.
 */
// OK if just using a single permanently connected device

void onewire_reset() {
    output_low(ONE_WIRE_PIN);       // pull the bus low for reset
    delay_us(500);
    output_float(ONE_WIRE_PIN);     // float the bus high
    delay_us(500);                  // wait-out remaining initialisation window
    output_float(ONE_WIRE_PIN);
}


/*
 * onewire_write(int8 data)
 * Arguments: a byte of data.
 * Description: writes a byte of data to the device.
 */
void onewire_write(int8 data) {
    int8 count;

    for(count = 0; count < 8; ++count) {
        output_low(ONE_WIRE_PIN);
        delay_us(2);                // pull 1-wire low to initiate write time-slot.
        output_bit(ONE_WIRE_PIN, shift_right(&data, 1, 0)); // set output bit on 1-wire
        delay_us(60);               // wait until end of write slot.
        output_float(ONE_WIRE_PIN); // set 1-wire high again,
        delay_us(2);                // for more than 1us minimum.
    }
}

/*
 * onewire_read()
 * Description: reads and returns a byte of data from the device.
 */
int onewire_read() {
    int count, data;

    for(count = 0; count < 8; ++count) {
        output_low(ONE_WIRE_PIN);
        delay_us(2);                // pull 1-wire low to initiate read time-slot.
        output_float(ONE_WIRE_PIN); // now let 1-wire float high,
        delay_us(8);                // let device state stabilise,
        shift_right(&data, 1, input(ONE_WIRE_PIN)); // and load result.
        delay_us(120);              // wait until end of read slot.
    }
    return data;
}
/*
 * ds1820_read()
 * Description: reads the ds18x20 device on the 1-wire bus and returns
 *              the temperature
 */

float ds1820_read() {
    int8 busy=0, temp1, temp2;
    signed int16 temp3;
    float result;

    //ds1820_configure(0x00, 0x00, 0x00);     //9 bit resolution

    onewire_reset();
    onewire_write(0xCC);            //Skip ROM, address all devices
    onewire_write(0x44);            //Start temperature conversion

    while(busy == 0)                //Wait while busy (bus is low)
        busy = onewire_read();

    onewire_reset();
    onewire_write(0xCC);            //Skip ROM, address all devices
    onewire_write(0xBE);            //Read scratchpad
    temp1 = onewire_read();
    temp2 = onewire_read();
    temp3 = make16(temp2, temp1);

    //result = (float) temp3 / 2.0;   //Calculation for DS18S20 with 0.5 deg C resolution
    result = (float) temp3 / 16.0;    //Calculation for DS18B20

    delay_ms(200);
    return(result);
}

/*
 * ds1820_configure(int8 TH, int8 LH, int8 config)
 * Description: writes configuration data to the DS18x20 device
 * Arguments: alarm trigger high, alarm trigger low, configuration
 */

void ds1820_configure(int8 TH, int8 TL, int8 config) {
    onewire_reset();
    onewire_write(0xCC);            //Skip ROM, address all devices
    onewire_write(0x4E);            //Write to scratchpad
    onewire_write(TH);
    onewire_write(TL);
    onewire_write(config);
}

void show_xy(int position, int single_number)
{
port_a=LED_POSITION[position];
port_b=LED_MAP[single_number];
}

main(){
//setup_timer_0 ( RTCC_DIV_256 | RTCC_INTERNAL );
setup_timer_0 (RTCC_INTERNAL | RTCC_8_BIT | RTCC_DIV_256);
set_timer0 (0);
enable_interrupts (GLOBAL );
enable_interrupts (INT_TIMER0);
set_tris_b(0); /* set port_b as outputs */
set_tris_a(0); /* set port_a as output */

port_b = 0; /* ZERO port_a & port_b */
port_a = 0;

while(1)
  {
   value = ds1820_read();
   if(value<0)
   {
   minus=0;
   value=value*-1;
   }
   else minus=1;
   single_number= (int)value%10;
   tens=(int)value/10;
   //temp=value-(int)value;
   delay_ms(400);
   }
}
#USE DELAY( CLOCK=4000000 )
#INT_TIMER0
void multiplexing_isr() {
if(minus!=1) {show_xy(3,11);}
delay_us(3210);
if(tens!=0) {show_xy(2,tens);}
delay_us(3210);
show_xy(1,single_number);
delay_us(3210);
show_xy(1,10);
delay_us(3210);
show_xy(0,less_than_one);
delay_us(3210);
}