- Published: Wednesday, 13 July 2011
- Written by Jon Chandler
- Hits: 6443
Here's another great article from Embedded Lab. The FVR (fixed voltage reference) is included in the 18Fk-series parts with various capabilities.
The reference voltage plays a very important role in any A/D conversion. It determines both the range and the resolution (Volt/Count) of the A/D conversion. Besides, the accuracy of the conversion also depends upon how stable the reference voltage is. Usually in PIC microcontrollers, the reference voltage for A/D conversion can be selected as the supply voltage itself or provided externally through one or more I/O pins. But the new enhanced mid-range family of 8-bit PIC microcontrollers have a built-in module that generates a stable reference voltage internally. It is called Fixed Voltage Reference (FVR) where the output is very stable and independent of the supply voltage (VDD). The output of the FVR can be configured to supply a reference voltage for A/D conversion internally. This article describes how to configure the FVR module to derive the reference voltage of 2.048 V for A/D conversion in PIC16F1827 microcontroller. The analog signal for this experiment is taken from the output of a LM34DZ temperature sensor. After the A/D conversion, the PIC16F1827 displays the temperature on a 2×8 character LCD.
Isn't this an awesome board layout on perfboard?
Related article from Embedded Lab: Voltage monitor for car’s battery and its charging system