18f4550 Analog Vref

boily · Joined: 27 Jan 2009 Posts: 19

Hi,

I started a project on a 16f877a and I was using a 3.3V Vref for the analog port.
I could set A0 to A2 as analog input and A3 as a Vref !

How can I right that for the 18f4550 ?
Can I still do it ?

Thanks

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Look in the ADC section of the 18F4550.h file. It tells how to do it.
It lists the constants to be used with setup_adc_ports().

boily · Joined: 27 Jan 2009 Posts: 19

yeah I look into that but can't find how to set the Vref :

boily · Joined: 27 Jan 2009 Posts: 19

Answer: setup_adc_ports(AN0|VSS_VREF);