Problem of Celsius and Fahrenheit scale digital thermometer using 8051 microcontroller (AT89C51)

[Kin]

Hello, i got a problem of this project

 

i made a PCB and sold all the component needed on it

 

but the temp was remain at 12 degree celsius?

circuit is the same

code is same

component is same

all components work fine

 

hope to see how fix this problem..

thankyou very much~

[AJISH ALFRED]

 

Hi Kin,

               Please check whether your ADC reference pin is getting the required 5V or not.

[Kin]

Hello

 

        My teacher taught us to get 2.5V to the 0804 pin9 (verf/2)

is there any go wrong here ?

[AJISH ALFRED]

 

Your teacher is right ! The internal gain of pin 9 of 0804 is 2. But somewhere in the datasheet I found that “voltage below 2.5 can be applied to pin 9″.

To get a reference voltage of exact 5V, all you have to do is to leave the pin 9 unconnected.

Sample circuits found in the datasheet also do it this way!

[Author]

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