8-bit Timer/Counter2 with PWM and Asynchronous Operation
Timer/Counter2 is a general purpose, single channel, 8-bit Timer/Counter module. The
main features are:
Features
Overview
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Single Channel Counter
Clear Timer on Compare Match (Auto Reload)
Glitch-free, Phase Correct Pulse Width Modulator (PWM)
Frequency Generator
10-bit Clock Prescaler
Overflow and Compare Match Interrupt Sources (TOV2 and OCF2A)
Allows Clocking from External 32 kHz Watch Crystal Independent of the I/O Clock
Many register and bit references in this section are written in general form.
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A lower case “n” replaces the Timer/Counter number, in this case 2. However, when
using the register or bit defines in a program, the precise form must be used, i.e.,
TCNT2 for accessing Timer/Counter2 counter value and so on.
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A lower case “x” replaces the Output Compare unit channel, in this case A.
However, when using the register or bit defines in a program, the precise form must
be used, i.e., OCR2A for accessing Timer/Counter2 output compare channel A
value and so on.
A simplified block diagram of the 8-bit Timer/Counter is shown in Figure 61. For the
actual placement of I/O pins, refer to Figure 2 on page 4. 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 “8-bit Timer/Counter Register Description” on page 151.
140
AT90CAN128
4250E–CAN–12/04
ATMEL [ ATMEL ]
