186
CHAPTER 9 TIMEBASE TIMER
9.1
Overview of Timebase Timer
The timebase timer, which is an 18-bit free-running counter (timebase timer counter)
that counts up in synchronization with the internal count clock (the source clock
frequency divided by 2), has the interval timer function to enable selection for four
types of interval times. Furthermore, it also has functions to supply operation clocks
including timer output for the oscillation stabilization wait time as well as the
watchdog timer.
■
Interval timer function
The interval timer function generates repetitive interval interrupt requests.
•
An interrupt request is generated when the bit for the interval timer in the timebase counter
overflows.
•
The bit for the interval timer (interval time) can be selected out of four types.
Table 9.1-1 shows the interval time of the timebase timer.
Table 9.1-1 Interval time of timebase timer
Internal count clock cycle
Interval cycle
2 / HCLK (0.5
μ
s)
2
12
/ HCLK (approximately 1.0 ms)
2
14
/ HCLK (approximately 4.1 ms)
2
16
/ HCLK (approximately 16.4 ms)
2
19
/ HCLK (approximately 131.1 ms)
HCLK: Oscillation clock
The value during operation of the oscillation clock at 4 MHz is shown in ( ).
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 ...
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