ADC value to lcd display doubts

[thannara123]

Hello experts , i want to know what value we get from an 8 bit ADC (0804) ?
Binary ,or hex ?
how it pass to LCD ?
i googled but the programs are available but not logic .
please help me ,.
any understandable c code

 

[Akalanka]

It is binary.
Datasheet says " The digital outputs vary from 0 to a maximum of 255".

To display it in a LCD -- you have to read the binary value (probably using a microcontroller) and drive the LCD accordingly.

 

[thannara123]

thats means we need to converts that binary to decimal for the LCD display ?

 

[Raady Here]

It all depends on how you are programming the LCD.

 

[Akalanka]

Yes.
You have to remember the reference voltage value.
datasheet says
"The step size can be adjusted by setting the reference voltage at pin9. When this pin is not connected, the default reference voltage is the operating voltage, i.e., Vcc. The step size at 5V is 19.53mV (5V/255), i.e., for every 19.53mV rise in the analog input, the output varies by 1 unit. To set a particular voltage level as the reference value, this pin is connected to half the voltage. For example, to set a reference of 4V (Vref), pin9 is connected to 2V (Vref/2), thereby reducing the step size to 15.62mV (4V/255). "
Let say
Your Vref = 5V
You get ADC result = 10001100 i.e decimal 140
your value to be display = 19.53mV x 140 = 2.73 V

 

[jayanth.devarayanadurga]

https://www.edaboard.com/threads/305683/

 

[thannara123]

i am not connected vref . thats 5 v, taken as step size 19.53.

i want a simple program to display .
including the conversion ?

 

[wp100]

thats means we need to converts that binary to decimal for the LCD display ?

Hi,

Your 8 bit ADC result 0000 0000 to 1111 1111 ( 0 to 255 decimal) needs to be converted to ASCII format for most lcds, which your compiler should easily do for you.

https://arduino.cc/en/Reference/ASCIIchart

 

[thannara123]

sir ,it need to convert in to corresponding voltage

 

[jayanth.devarayanadurga]

If ADC value is 255 and max voltage is 5V for 255. So 255 * 5.0 / 255 = 5.0 which is the volts.

If adc value is 100 then 100 * 5 / 255 = 1.9 approx.

If you change the scale to say 300 V then

255 * 300 / 255 = 300

ADC value * scale / 255 for 8 bit adc.

 

[thannara123]

acan i get a sample binary to decimal conversion pgm in c ?/

 

[jayanth.devarayanadurga]

The value of adc result will be in binary form in the hardware but it doesn't matter whether the value is represented by binary or hex or decimal. To convert it to character you just add 0x30 or 48d (decimal) to it.

0 + 0x30 = '0' which can be print on LCD.

 

[thannara123]

i have added the 0x30 with value and displayed ,but some asci higher value shows

 

[jayanth.devarayanadurga]

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Code C - [expand]
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lcdcom(0x80);
lcddata(adcval / 100 + 48);
lcdcom(0x81);
lcddata((adcval / 10) % 10 + 48);
lcdcom(0x82);
lcddata(adcval % 100 + 48);

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