Hi
This code is written in order to read a sensor value (must be a humidity sensor here) and display "Rel.Humidity" on a LCD.
In this code average of 11 consecutive sensor readings is made and then it is converted to relative humidity value by means of some sort of a formula. This all is happening inside display() function.
Since 8051's don't have inbuilt ADCs therefore an 8 bit ADC IC must be connected to it with PORT1.