AT89LP428-20MU ATMEL [ATMEL Corporation], AT89LP428-20MU Datasheet - Page 61

• Manufacturer Part Number: AT89LP428-20MU
• Description: 8-bit Microcontroller with 4K/8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

13. Compare/Capture Array
3654A–MICRO–8/09
Figure 12-8. Timer 2 in Clock-out Mode
The AT89LP428/828 includes a four channel Compare/Capture Array (CCA) that performs a
variety of timing operations including input event capture, output compare waveform generation
and pulse width modulation (PWM). Timer 2 serves as the time base for the four 16-bit com-
pare/capture modules. The CCA has the following features:
The block diagram of the CCA is given in
register and a 16-bit data register. The channel registers are not directly accessible. The CCA
address register T2CCA provides an index into the array. The control, data low and data high
bytes of the currently indexed channel are accessed through the T2CCC, T2CCL and T2CCH
registers, respectively.
Each channel can be individually configured for capture or compare mode. Capture mode is the
default setting. During capture mode, the current value of the time base is copied into the chan-
nel’s data register when the specified external or internal event occurs. An interrupt flag is set at
the same time and the time base may be optionally cleared. To enable compare mode, the
CCMx bit in the channel’s control register (CCCx) should be set to 1. In compare mode an inter-
rupt flag is set and an output pin is optionally toggled when the value of the time base matches
the value of the channel’s data register. The time base may also be optionally cleared on a com-
pare match.
• Four 16-bit Compare/Capture channels
• Common time base provided by Timer 2
• Selectable external and internal capture events including pin change, timer overflow and
• Symmetric/Asymmetric PWM with selectable polarity
• Multi-phasic PWM outputs
• One interrupt flag per channel with a common interrupt vector
comparator output change
T2EX PIN
T2 PIN
OSC
÷TPS
Transition
Detector
Figure
C/T2
EXEN2
TR2
13-1. Each channel consists of an 8-bit control
RCAP2L
TL2
÷2
EXF2
AT89LP428/828
RCAP2H
TH2
Interrupt
T2OE
Timer 2
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