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Im working ADC in PIC24FJ64GA002 microcontroller using proteus simulation. I've a doubt regards AD port configuration register. I've connected a potentiometer in AN12 pin and channel was selected. The problem is even i comment the below analog/digital mode selection config bit code, its working. I can able to get ADC value.

AD1PCFGbits.PCFG12 = 0;

Is not necessary to mention the analog or digital mode for the corresponding pins?

Code:

 void InitADC(void)
{
// *******************************
// 1. Configure the A/D module
// *******************************
// a) Select port pins as analog inputs(AD1PCFG<15:0>)
AD1PCFGbits.PCFG0  = 1; //PCFG(12-0) 1:Digital mode, 0:Analog mode
AD1PCFGbits.PCFG1  = 1; 
AD1PCFGbits.PCFG2  = 1; 
AD1PCFGbits.PCFG3  = 1; 
AD1PCFGbits.PCFG4  = 1;
AD1PCFGbits.PCFG5  = 1; 
AD1PCFGbits.PCFG9  = 1;
AD1PCFGbits.PCFG10 = 1; 
AD1PCFGbits.PCFG11 = 1; 
AD1PCFGbits.PCFG12 = 1; <== **here i set 1**.
AD1PCFGbits.PCFG15 = 1;

enter image description here

Thanks.

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  • \$\begingroup\$ "I can able to get ADC value" - if you are able to get the value, what is the question. Maybe you meant to say "I am unable"? \$\endgroup\$
    – Andy aka
    Aug 13, 2015 at 13:27
  • \$\begingroup\$ Hi @Andyaka Me too can able to get the value. My question is according to the datasheet PCFG bit is to setting analog or digital mode. Since i use potentiometer i set PCFG12 bit as 0 for analog, its working it make sense. strange is even its working when i didnt specify the analog mode in PCFG12 bit and also its working when i set digital mode. Sorry for the poor english. \$\endgroup\$
    – user6161
    Aug 13, 2015 at 13:39

1 Answer 1

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In most PIC micros, analog mode for a pin is turned on at power-on, i.e., you don't need to do anything to use a pin as analog input (given it is capable of it). Set PCFG to 1 and ADC will stop reading your pot.

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  • \$\begingroup\$ Thanks for the reply. Ok.But i set PCFG to 1, ADC is still reading. Let me post the code and screenshot in my main post. \$\endgroup\$
    – user6161
    Aug 13, 2015 at 14:07
  • \$\begingroup\$ I was talking about physical micro. I'm not familiar with the simulator you're using. \$\endgroup\$ Aug 13, 2015 at 15:02
  • \$\begingroup\$ oh ok. Waiting for physical micro. I will test it and let you know. Thanks Mazurov. \$\endgroup\$
    – user6161
    Aug 13, 2015 at 16:47

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