Rev. 1.0, 02/00, page 388 of 1141
21.1.2
Block Diagram
Figure 21.1 shows a block diagram of the prescalar unit.
φ
PWM3
ICR1
PCSR
18-bit free running counter (FRC)
φ
w/128
Prescalar W
φ
/131072 to
φ
/2
Prescalar S
Internal data bus
MSB
LSB
φ
w/4
φ
w/8
φ
w/16
φ
w/32
φ
/32
φ
/16
φ
/8
φ
/4
Interrupt
request
5-bit counter
pin
Stable oscillation
wait time count output
2
12
2
15
2
8
2
7
2
7
2
0
TMOW
pin
MSB
LSB
8 bits
6 bits
8 bits
PWM2
PWM1
PWM0
[Legend]
ICR1
PCSR
: Input capture register 1
: Prescalar unit control/status register
TMOW
: Input capture input pin
: Frequency division clock output pin
Figure 21.1 Block Diagram of Prescalar Unit