[Solved]Project: Digital Room Thermometer using LM35 sensor and 8051 Microcontroller

it is not certain . but basically pin 21 to 28 and pin 10,11,16 shows value of 1.5 volt sometimes. value is also not stable. after some time, the same pins give reaing of 5 volt or may be 0 volt also. readings are totally erratic

well you might be measuring with voltmeter.. these are data lines. so there might be transactions going on on these lines. you will not be able to measure it. Its better use a scope if you want to see if everything is fine or not.

We connected those pins with cro also. . only the clock pins( 18 and 19) and capacitor connected to pin 9 is giving some output. other pins are dead. no amplitude, no frequency

I dont see problems anywhere... try to change controller and test again.

changing controller? another at89s52 or other chip of 8051 family? actually we dont have any universal burner. so only chip it can burn is at89s52.

will try again tomorrow and let u know .

I meant a different 89S52... just to make sure everything is ok on controller side.

ok . will try to find another controller and will test it. one qn, is there any way to test microcontroller without using programming whether it is working or not?

there is no way to test controller without programming it. You can test your controller using simple LED toggle program. you will come to know if controller is working or not.

we will test it by led blinking program.. can u convert this c program to hex file? i think we may have some problems creating hex file...









sfr P2 = 0xA0;

void delay()
{
int i;
for(i=0;i<15000;i++)
{

}
}

void main()
{
while(1)
{
P2 = 0xFF;
delay();
P2 = 0x00;
delay();
}
}