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CHAPTER 13 8/16-BIT UP/DOWN COUNTER/TIMER
In the mode at frequency multiplied by 2, at the timing of both the rising and falling edges of the
BIN pin, counting is done as required by checking for the AIN pin value. Count operations in this
case are as follows:
•
Incremented if the AIN pin value detected at the rising edge of the BIN pin is "H"
•
Decremented if the AIN pin value detected at the rising edge of the BIN pin is "L"
The AIN pin value detected at the falling edge of the BIN pin is selected from the following two
types 1) and 2):
1) Decremented if the AIN pin value detected at the falling edge of BIN pin is "H"
Incremented if the AIN pin value detected at the falling edge of the BIN pin is "L"
2) Decremented if the AIN pin value detected at the falling edge of the BIN pin is "L"
Incremented if the AIN pin value detected at the falling edge of the BIN pin is "H"
Figure 13.5-1 Outline of phase difference count mode (at frequency multiplied by 2) operation
AIN pin
BIN pin
Count in falling edge detect 1)
+1
0
1
Count value
Count in falling edge detect 2)
+1
0
1
Count value
In the mode at frequency multiplied by 4, the AIN pin value is checked for counting at the timing
of both the BIN pin rising and falling edges. BIN pin value is checked for counting at the timing
of both the AIN pin rising and falling edges. Count operations for such cases are described
below.
•
Incremented if the AIN pin value detected at the rising edge of the BIN pin is "H"
•
Decremented if the AIN pin value detected at the rising edge of the BIN pin is "L"
•
Decremented if the AIN pin value detected at the falling edge of the BIN pin is "H"
•
Incremented if the AIN pin value detected at the falling edge of the BIN pin is "L"
•
Decremented if the BIN pin value detected at the rising edge of the AIN pin is "H"
•
Incremented if the BIN pin value detected at the rising edge of the AIN pin is "L"
•
Incremented if the BIN pin value detected at the falling edge of the AIN pin is "H"
•
Decremented if the BIN pin value detected at the falling edge of the AIN pin is "L"
278
+1
+1
+1
+1
2
3
4
5
-1
+1
-1
+1
0
1
0
1
-1
+1
-1
-1
4
5
4
3
+1
+1
+1
-1
2
3
4
3
-1
-1
-1
2
1
0
+1
-1
+1
4
3
4
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