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CHAPTER 25 PWC TIMER (ONLY MB90485 SERIES)
25.5.1 Operations of the Timer Function
This timer is an up-count (incrementing) timer providing both reload and one-shot
operations.
■
Operation of timer functions
After the timer starts, its value is incremented at each pulse of the count clock. If an overflow
occurs in the range "FFFF
H
" --> "0000
H
", an interrupt request may be generated. If an overflow
is generated, the following operations may be performed depending on the mode:
•
In one-shot mode: Counting stops
•
In reload mode: Reload register data is reloaded into the timer to restart counting.
Figure 25.5-1 shows the operations of the timer functions in one-shot mode and reload mode.
Figure 25.5-1 Operations of timer functions
[One-shot mode]
[Reload mode]
Timer count value
*
*
*
*
*
FFFF
H
0000
H
FFFF
H
0000
H
Overflow
Overflow Overflow
Overflow Overflow Overflow
Overflow
Writing to PWCR
(Restarting prohibited)
Time
Time
(Solid line: timer count value)
Timer start
Timer
start
Timer start
OVIR flag
set/timer stop
OVIR flag
set/timer stop
Timer
stop
Reload
Reload
Reload Reload Reload
Reload
Reload
PWCR
write
Restart
*: OVIR flag set
PWCR write value
Summary of Contents for MB90480 Series
Page 2: ......
Page 4: ......
Page 10: ...vi ...
Page 128: ...106 CHAPTER 4 RESET ...
Page 174: ...152 CHAPTER 6 LOW POWER CONSUMPTION MODE ...
Page 198: ...176 CHAPTER 7 MODE SETTING ...
Page 220: ...198 CHAPTER 9 TIMEBASE TIMER ...
Page 238: ...216 CHAPTER 11 WATCH TIMER ...
Page 280: ...258 CHAPTER 12 16 BIT INPUT OUTPUT TIMER ...
Page 406: ...384 CHAPTER 17 8 10 BIT A D CONVERTER ...
Page 478: ...456 CHAPTER 20 CHIP SELECTION FACILITY ...
Page 494: ...472 CHAPTER 21 ADDRESS MATCH DETECTION FUNCTION ...
Page 498: ...476 CHAPTER 22 ROM MIRROR FUNCTION SELECTION MODULE ...
Page 526: ...504 CHAPTER 23 2M 3M BIT FLASH MEMORY ...
Page 536: ...514 CHAPTER 24 EXAMPLES OF MB90F481B MB90F482B MB90F488B MB90F489B SERIAL PROGRAMMING ...
Page 570: ...548 CHAPTER 25 PWC TIMER ONLY MB90485 SERIES ...
Page 688: ......