192
CHAPTER 13 WATCH PRESCALER
13.1
Overview of Watch Prescaler
The watch prescaler is a 15-bit down-counting, free-run counter, which is synchronized
with the subclock divided by two. It has an interval timer function that continuously
generates interrupt requests at regular intervals.
■
Interval Timer Function
The interval timer function continuously generates interrupt requests at regular intervals, using the subclock
divided by two as its count clock.
•
The counter of the watch prescaler counts down and an interrupt request is generated every time the
selected interval time has elapsed.
•
The interval time can be selected from the following four types:
Table 13.1-1 shows the interval times of the watch prescaler.
F
CL
: Subclock
The values in parentheses represent the values achieved when the subclock operates at 32.768kHz.
Note:
The watch prescaler cannot be used in single system clock product.
Table 13.1-1 Interval Times of Watch Prescaler
Internal count clock cycle
Interval time
2/F
CL
(61.0
μ
s)
2
11
x 2/F
CL
(125ms)
2
12
x 2/F
CL
(250ms)
2
13
x 2/F
CL
(500ms)
2
14
x 2/F
CL
(1.00s)
Содержание F2 MC-8FX Family
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Страница 35: ...21 CHAPTER 2 HANDLING DEVICES This chapter gives notes on using 2 1 Device Handling Precautions ...
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Страница 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Страница 43: ...29 CHAPTER 4 MEMORY ACCESS MODE This chapter describes the memory access mode 4 1 Memory Access Mode ...
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