That was exactly why I mentioned the 16F628! With the exception of the configuration word and the fact that you have to put in the instructions to disable the on chip comparator, the code for the 628 is identical to the code for an F84, and the pinout is identical as well.
For the config word I usually use -
This code allows for -
External Master Clear
Power Up Timer Enabled
Watchdog Timer Disabled
Code and Data Code Protection Disabled
Low Voltage Programming Disabled
Brown Out Detection Disabled
High Speed Oscillator (I run a 16MHz crystal)
If you want to run something slower like a 4MHz crystal, your config word would be -
Then when you set up your ports as input and output, you add in these instructions to disable the on chip comparator -
Other than that, the rest of the code remains the same between the 16F84 and the 16F628.
As you gain knowledge in PIC programming you'll find that the entire 16F series of PICs uses an identical instruction set. However, knowing how to set the configuration word among a few other things requires knowing the chip itself and what hardware is on chip so that you know how to configure those features for your particular application.