STM32F4

Using Arduino Microcontrollers
12

I see this a lot | its the Or command yeah?, whats it do in the above line?

it is the bitwise OR (as opposed to the logical or boolean OR) and it "adds up" bittpatterns

The rules are

0 or 0 = 0
0 or 1 = 1
1 or 0 = 1
1 or 1 = 1

so if you have 2 bytes A=00001111 and B=00111100 then C= A|B = 00111111 it is bitwised or-ed

This technique is used often to set registers and masks, more see - Arduino Playground - BitMath