newbie pls help

hello

i have a question i need an output
of 0 to 9V on RA0 on a
pic16f84 @ the same time be able
to display it on an LCD. My question is
there a device w/c can directly
communicate w/a pic16f84 and
at the same time control the voltage output.
if there isnt how do i go about it.
i was thinkin digital potentiometer.

thanx much

Hi do u mean make a sorta power suply, with the PIC controlling the output voltage, and displaying the voltage output on an LCD?

if so the easyest way is probably to use a high quality DAC. Depending on your needs a 24bit seriel one would probably suffice, thou it would take a LOT of cailbration boardem + reliable data sheet maths to figure out what value will give you what voltage.

Some DACs u can just interface serially and have them take a 9v rail, as the maximum, depending on ur application u might need to put some current amplification on the end of it. Some DACs u might need to use to control a MOSFET or somthing to allow full switching of upto 9v.

It might be possible to use an ADC built into the pic to act as a way of deteticting the voltage output, and then make the DAC chase until it hits the right voltage.

You might find it worth while going for a PIC with an SPI (Serial Protocol Interface) as most DACs of high resolution are seriel driven.