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ihsanbu
Joined: 14 Oct 2006
Posts: 27
Location: islamabad,pakistan
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| hi all help in coding using ccs c |
 Posted: Sun Aug 07, 2011 2:20 pm |
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How can I get adc value (10BIT) using PIC18f452 mcu? Can I get desired value from sample voltages(0>>5volt) at which i decided some control action?
e.g
If adc read routine read the value 3volt dc then I want to switch ON the portc.1 and send this value to Serial port.
thank you |
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MiniMe
Joined: 17 Nov 2009
Posts: 50
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| Posted: Sun Aug 07, 2011 4:20 pm |
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Hi ihsanbu
I believe i got just the thing your looking for.
If it a function that inputs a ADC value ( number 0 - 1023, 2^10 bit ) and output (returns) a voltage varuble that is equal* to ADC value.
This function do use ADC limits. Upper limit and lower limit: references - min and max. Look it up. Normal (without references) ADC assigned 10bit number to voltage 0-5V. This function only sees* voltage values between 1,2 - 3,4V. It is for increasing accuracy as voltages below 1,2 and 3,4 are not used.
| Code: |
unsigned int16 ADC2voldid(int16 adc_v22rtus)
{
//Muutujate deklareerimine
unsigned int32 voldid;
unsigned int16 voldid_16;
//Muutujasse "adc_v22rtus" l2heb ADC registi v22rtus
//adc_v22rtus = adc_keskmine(0);
//Valem, et teisendada ADC v22ruts -- > Pingeks (V)
//100000 on ylemise ja alumise piiri vahe, antud juhul 3,4V - 1,2V = 2.2V
voldid = (unsigned int32) (( adc_v22rtus * 220000));
voldid_16 = (unsigned int16) ( (voldid >> 10) / 100);
voldid_16 += 1200; // on alumine piir, antud juhul 1.2V;
//Funktsiooni tagatis (v22rtus)
//printf("\n\rvoldid_16 %Ld",voldid_16);
return voldid_16;
}
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The ADC value in variable "int16 adc_v22rtus", you can get from read_adc( ) function. Look up "read_adc( )" from CCS help.
So your code part should look like:
You should put tease 2 function into loop. From function ADC2voldid you will get value that represent voltage something like int16 value 302. it should mean that its around 3 V.
| Code: |
while(1) {
if( ADC2voldid( read_adc(0) ) > 300) { //0 means ADC pin 0.
output_c(0b11111111); // port C all pins high
Printf("\n\rVoltage is over 3V, exactly %Lu",ADC2voldid( read_adc(0) ); // outputs string by serial port.
}
else{
output_c(0b00000000); // port C all pins low
}
}
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I hope i understood your problem. I wish you good luck with your task. |
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ihsanbu
Joined: 14 Oct 2006
Posts: 27
Location: islamabad,pakistan
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| thank you |
| Posted: Mon Aug 08, 2011 2:11 pm |
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thank you
_________________
ihsan ullah khan
Embedded Designer Since 2003 |
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