Fujitsu MB90460 Series, Hardware Manual, Page: 466 / 739

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CHAPTER 16 PWC Timer
16.6 Operation of the PWC Timer
The PWC timer is the multi-functional timer based on the 16-bit up-count timer and
contains the count input pin and 8-bit input divider. The block has two main functions:
timer function and pulse-width count function. Both the timer function and the pulse-
width count function enable the selection of two types of count clocks.
■
Timer Function
The timer function is the up-count timer that enables selection of the operation in single mode or reload
mode.
When the timer is started, a timer count is performed at each count clock.
When an overflow occurs in the range from FFFF
H
to 0000
H
, an interrupt request is issued.
If an overflow occurs, the following occurs:
During single mode, count is discontinued (see Figure 16.6-1).
During reload mode, the reload register contents are reloaded to the timer and the count is restarted (see
Figure 16.6-2).
Figure 16.6-1 Timer Operation (Single Mode)
Timer count value
FFFF
H
0000
H
Overflow Overflow
Write to
PWC
(Restart is invalid)
Timer starts
OVIR flag setting, Timer stops
Timer starts
OVIR flag setting, Timer stops
Time