1 features, 2 overview, Atmega128rfa1 – Rainbow Electronics ATmega128RFA1 User Manual
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8266A-MCU Wireless-12/09
ATmega128RFA1
18 16-bit Timer/Counter (Timer/Counter 1, 3, 4, and 5)
18.1 Features
•
True 16-bit Design (i.e., allows 16-bit PWM)
•
Three independent Output Compare Units
•
Double Buffered Output Compare Registers
•
One Input Capture Unit
•
Input Capture Noise Canceller
•
Clear Timer on Compare Match (Auto Reload)
•
Glitch-free, Phase Correct Pulse Width Modulator (PWM)
•
Variable PWM Period
•
Frequency Generator
•
External Event Counter
•
Numerous independent interrupt sources
o
TOV1, OCF1A, OCF1B, OCF1C, ICF1
o
TOV3, OCF3A, OCF3B, OCF3C, ICF3
o
TOV4, OCF4A, OCF4B, OCF4C
o
TOV5, OCF5A, OCF5B, OCF5C
18.2 Overview
The 16-bit Timer/Counter unit allows accurate program execution timing (event
management), wave generation and signal timing measurement.
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 i.e., TCNT1 for accessing Timer/Counter1 counter value and
so on.
A simplified block diagram of the 16-bit Timer/Counter is shown in Figure 18-1. For the
actual placement of I/O pins, see section
"Pin Configurations" on page 2
. 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 locations are listed in the section
.
The Power Reduction Timer/Counter1 bit, PRTIM1, in
must be written to zero to enable Timer/Counter1 module.
The Power Reduction bits of Timer/Counter3 (PRTIM3), Timer/Counter4 bit (PRTIM4)
and Timer/Counter5 (PRTIM5) in
"PRR1 – Power Reduction Register 1" on page 168
must be written to zero to enable the respective Timer/Counter module.
Note, note the complete Timer/Counter I/O functionality is provided for each
Timer/Counter module depending on the available I/O pins.