Finition de mon programme ccs c compiler

bonjour a tous!
une partie de mon pfe consiste aprogrammer la carte electronique a base de PIC, tout va bien mais ISIS m'indique un petit probleme lors de la simulation : "[PIC16 ADC] PC=0x0.. ADC conversion strated before 'wait' time has expired following previous conversion or channel change"

voila mon programme:
#include<16f877.h>
#use delay (clock=4000000)
#use rs232 (baud=9600,rcv=PIN_C7, xmit=PIN_C6)
#fuses XT,NOWDT,NOPROTECT,NOLVP

#include<math.h>
#include <stdlib.h>

#define use_portb_lcd TRUE
#include <lcd.c>


//affichage sur ecran
void ecran (long int x)
{
printf("Temperature1:%3ld C\\r",x);
delay_ms(1000);
}
void ecran1 (long int y)
{
printf("Temperature2:%3ld C\\r",y);
printf("-----------------------------------------------------\\r");
delay_ms(1000);
}



//Affichage Sur LCD
void affichage (long int x)
{

lcd_gotoxy(1,1);
printf(lcd_putc,"t1=%3ldC",x);

}
void affichage1 (long int y)
{
lcd_gotoxy(9,1);
printf(lcd_putc,"t2=%3ld C",y);
}





//La Lecture et la converission A/N du tensiondu por A/N et elle retourne la temperature equivalente
int lecture ()
{

float valr,val,T;
float B=9.7,A=13.6;//Les variables caracterstique de notre capteur de température
float Rc;
long int t1;
val=read_adc(ADC_START_AND_READ);

valr=(val*2.5)/128;
Rc=((1000*valr)/(5-valr));

T=B/(log(Rc/A));
t1=ceil(T);
return(t1);
}


//La Lecture et la converission A/N du tensiondu por A/N et elle retourne la temperature equivalente
int lecture1 ()
{


float valr1,val1,T1;
float B=9.7,A=13.6;//Les variables caracterstique de notre capteur de température
float Rc1;
long int t2;
val1=read_adc(ADC_START_AND_READ);

valr1=(val1*2.5)/128;
Rc1=((1000*valr1)/(5-valr1));

T1=B/(log(Rc1/A));
t2=ceil(T1);
return(t2);
}



//Programme Principale
void main()


{
long int val_res, val_res1;
printf(" starting convertion : \\r");
delay_ms(1500);
lcd_init();
SETUP_ADC_PORTS(ALL_ANALOG);
SETUP_ADC(ADC_CLOCK_INTERNAL);

while(true)
{
SET_ADC_CHANNEL(0);
val_res=lecture();
ceil(val_res);
affichage(val_res);
delay_us(400);
ecran(val_res);
delay_us(400);

SET_ADC_CHANNEL(1);
val_res1=lecture1();
ceil(val_res1);
affichage1(val_res1);
delay_us(400);
ecran1(val_res1);
delay_us(400);


}

}