I know this is pretty basic but so am I. Setting up the tutorial for the 74HC595 shift register, noted the controller shown is an NG, Mine is a MEGA 2560. The pins used in the tutorial, 8,11 and 12 are shown as digital, on my MEGA they are all PWM, Will this make a difference in the operation of the circuit?? Should I switch to just digital pins?? Any info appreciated.
Any I/O pin can be used (except 0 and 1, which are used for serial communication and generally shouldn't be used for anything unless you really know what you're doing and it's ramifications)
analog pins, PWM pins, and digital pins all have the same capabilities of a basic digital pin (the PWM and analog pins just have additional capabilities, a fact which is often not recognized by new arduino users, particularly for "analog pins"), and will work with shiftOut.
(There is one exception to analog pins working as digital pins: pins A6 and A7 on boards based on the SMD version of the atmega328p - these only work with analogRead, and are the only pins like that within the entire AVR product line, as far as I know - they are present only in the SMD versions of the chip, and appear to have been added as an afterthought when they released the SMD version, ie "what do we do with the extra 4 pins" - two became an extra pair of supply pins, and the other two became the analog-only pins)
Note that the tutorial omits a required component, and may not function reliably in all operating conditions as a result - you should have a 0.1uF ceramic cap between Vcc and Gnd of the shift register, placed as close as possible to those pins. You generally need one on any digital IC, unless stated otherwise in the datasheet. Quite frankly, the tutorials on the official website are pretty lousy, especially when it comes to the hardware.
There are perhaps a hundred tutorials on the web on how to use the ‘595 shift register.
It is always good practice to post a link to what you’re referring to as we cannot see what you see on your computer screen.