The compound bitwise OR operator (|=) is often used with a variable and a constant to "set" (set to 1) particular bits in a variable.
x |= y; // equivalent to x = x | y;
x
a char, int or long variable
y
an integer constant or char, int, or long
First, a review of the Bitwise OR (|) operator
0 0 1 1 operand1
0 1 0 1 operand2
----------
0 1 1 1 (operand1 | operand2) - returned result
Bits that are "bitwise ORed" with 0 are unchanged, so if myByte is a byte variable,
myByte =| B00000000 = myByte;
Bits that are "bitwise ORed" with 1 are set to 1 so:
myByte | B11111111 = B11111111;