The design is based on a PIC 16F877 and consists of a digital voltmeter application reading the
ADC and displaying the result on the OEM4 LED, in addition a demo of the display capabilities
is also provided.  Set RD7=0 for voltmeter and RD7=1 for display demo.

In this application the Vref+ is the supply voltage (+4.95V on my sample) and
Vref- is 0V. Scaling is 4.88mV per division but there will be some error
depending on the exact value of the supply.  In real life it may be better to use
a reference of say 4.096V as the ADC has 10bit resolution (1024 steps) then each step
is of equal value and calibration is easy as it is not dependant on the setting of the
power supply.

The C compiler was the Hi tech Compiler PICC V8.01PL3.

The delay routines delay.c and delay.h are taken from the Hi-Tech samples.

The checksum of the code is 232E.

