Fujitsu FR81S User Manual
CHAPTER 27: UP/DOWN COUNTER
6. Operation and Setting Procedure Examples
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : UP/DOWN COUNTER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
FUJITSU SEMICONDUCTOR CONFIDENTIAL
32
6.4. Operation in the Phase Difference Count Mode
(Multiply-by-Four)
This section explains the operation in the phase difference count mode (multiply-by-four).
Overview
This mode involves counting the phase difference of the signal input from two external signal input pins.
This mode is suitable to count the phase difference of phases A and B of encoder outputs.
This mode is suitable to count the phase difference of phases A and B of encoder outputs.
When a rising or falling edge is detected from the AIN or BIN pin, the input level from the other pin is
verified to count up or down the phase difference of the AIN and BIN pins.
verified to count up or down the phase difference of the AIN and BIN pins.
Counting up or counting down is determined depending on the combination of the edge to be detected and
the input level.
the input level.
Table 6-4 lists the count methods.
Table 6-4 Count Methods
Edge detection
pin
Detection
edge
Level check pin
Input level
Count direction
BIN pin
Rising edge
AIN pin
"H" level
Counting up
"L" level
Counting down
Falling edge
"H" level
Counting down
"L" level
Counting up
AIN pin
Rising edge
BIN pin
"H" level
Counting down
"L" level
Counting up
Falling edge
"H" level
Counting up
"L" level
Counting down
Moreover, the following three types of functions can be used in the phase difference count mode
(multiply-by-four).
(multiply-by-four).
· Reload function
· Compare function
· Reload compare function
· Compare function
· Reload compare function
MB91520 Series
MN705-00010-1v0-E
1039