Digital Clock Startup Project

To start off my experimentation with pic microcontrollers, I was thinking of building and later expanding on this project:



I am a fair C programmer, but low level when it comes to circuits and parts.

The project calls for a PIC16F628-04/P. I will start with this one for now.
(Later, maybe I could use a 16F877A.)

So, I looked this part up on the Allied Electronics web site and there are 40 types.

What does the "-04/P" in the part number stand for?

Please feel free to comment, also, on other aspects of this project. Thanks.

From the datasheet:
https://ww1.microchip.com/downloads/en/DeviceDoc/40300C.pdf
The "P" stands for PDIP packaging (the throughhole hold)
the -04 means it's up to 4MHz, I think it comes in -20 as well for 20MHz

You can look for the PIC16F628-I/P
The "I" stands for the operating temperature, if you need extreme operating conditions you can get the -E/P
Here is an example of one available from Mouser:
PIC16F628A-I/P Microchip Technology Microcontrollers (MCU)

Perhaps I should look at the choice of microcontroller and the use of an accurate external crystal clock now.

My thought is to jump up to the PIC16F877A(40 pin) and find a circuit for the crystal clock divided down if needed?