308
CHAPTER 14 16-BIT RELOAD TIMER
14.4.3 Internal Clock Mode (One-Shot Mode)
The counter is in synchronization with the internal count clock in this mode to count
down the 16-bit counter and generate an interrupt request to the CPU at counter
underflow. It also outputs a square wave from the TOT pin to indicate that counting is
in progress.
■
Operation in internal clock mode (One-Shot Mode)
When count operation is allowed (TMCSR: CNTE=1) and the timer is started by the software
trigger bit (TMCSR: TRG) or external trigger, count operation will start. When both the count
enable bit and software trigger bit are set to "1" at the same time, counting will start with counter
allowance. If the counter value causes an underflow ("0000
H
"
→
"FFFF
H
"), the counter stops at
"FFFF
H
", and the timer interrupt request flag (UF) is set to "1". If the enable bit for interrupt
request (INTE) is set to "1", an interrupt request occurs.
The TOT pin outputs a square wave to indicate that counting is in progress.
❍
Software trigger operation
The counter is started as soon as the TRG bit of the timer control status registers (TMCSR) is
set to "1". Figure 14.4-7 shows the software trigger operation in one-shot mode.
Figure 14.4-7 Count operation in one-shot mode (software trigger operation)
Count clock
Counter
Data load signal
UF bit
CNTE bit
TRG bit
TOT pin
Waiting for start trigger input
T : Machine cycle
* : It takes 1T from trigger input to loading reload data.
Reload
data
Reload
data
0000
H
FFFF
H
0000
H
FFFF
H
T*
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: ......