How to set one pin as ANALOG all others as DIGITAL, and Vref=Vdd ?

[sayzer]

For F877,

On PortA, how do we set AN0 as analog, all others as digital and Vref=Vdd?
I am trying to have one analog channel and remaining pins as all digital on this port.

Thanks for the help in advance.


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[paul borgmeier]

Set bits 3-0 of ADCON1 to 1110 (as described in the 877 Datasheet DS30292C, page 112) and you will be all set.

Paul Borgmeier
Salt Lake City, Utah
USA

[sayzer]

Thank you Paul.

In this case, the table shows me, as you already pointed, the following explanation for it; just as I need.

ADCON1 REGISTER for bit3-0: 1110

Meaning that:
AN7=Digital
AN6=Digital
AN5=Digital
AN4=Digital
AN3=Digital
AN2=Digital
AN1=Digital
AN0=Analog
Vref+=Vdd
Vref-=Vss


After setting the channels and the Vref with Bit3-0 as above, then I need to set Bit7 as 1=Right justified. Then, Bit6-5-4 are left untouched as they are 0.

Finally, I come up with an ADCON1 register as follows.

ADCON1=%10001110

I also set ADCON0= %11000001 to match ADCON1.

and it works.

Thanks again for the guidance Paul.