Many register and bit references in this section are written in general form: However, when using the register or bit definitions in a program, the precise form must be used, i.e., TCNT2 for accessing Timer/Counter2 counter value.

The following definitions are used throughout the section:

Table 1. Definitions
Constant Description
BOTTOM The counter reaches the BOTTOM when it becomes zero (0x00).
MAX The counter reaches its maximum when it becomes 0xFF (decimal 255).
TOP The counter reaches the TOP when it becomes equal to the highest value in the count sequence. The TOP value can be assigned to be the fixed value 0xFF (MAX) or the value stored in the OCR2A Register. The assignment is dependent on the mode of operation.