Using VRef as a D/A output

[Azaruk]

I am using SRF04 in a sonar application.

I need the range to be displayed on an LED bargraph - LM3914 prefrably.

I have the SRF04 echo captured through the CCP module, which results in a 16-bit value.

How do I scale the 16-bit value into a 4-bit representation to present to the VRef module to give me a voltage level proportional to the SRF04 echo signal length.

I'm sure there's a imple solution, but my mind has gone blank over this, and what little hair I have left is steadily being pulled out!

Any ideas?

 

[plusminus]

One very simple solution is to use only the 4 MSB of the 16 bit signal directly to the 4 bit of the led bar.

An other solution can be to convert the 16bit value to a dc value with a D/A converter. Then use the dc value direct to the input of the LM3914.