Datasheet

85
7734Q–AVR–02/12
AT90PWM81/161
11. Reduced 16-bit Timer/Counter1
The 16-bit Timer/Counter unit allows accurate program execution timing (event management).
The main features are:
•
Clear timer on compare match (auto reload)
• One input capture unit
• Input capture noise canceler
• External event counter
• Two independent interrupt sources (TOV1, ICF1)
11.1 Overview
Most register and bit references in this section are written in general form. A lower case “n”
replaces the Timer/Counter number, and a lower case “x” replaces the Output Compare unit
channel. However, when using the register or bit defines in a program, the precise form must be
used, that is, TCNT1 for accessing Timer/Counter1 counter value and so on.
A simplified block diagram of the 16-bit Timer/Counter is shown in Figure 11-1 on page 86. For
the actual placement of I/O pins, refer to Table 2-2 on page 6. CPU accessible I/O Registers,
including I/O bits and I/O pins, are shown in bold. The device-specific I/O Register and bit loca-
tions are listed in the “16-bit Timer/Counter Register Description” on page 97.
The PRTIM1 bit in “Power Reduction Register” on page 46 must be written to zero to enable
Timer/Counter1 module.