
TIMER A
7902 Group User’s Manual
9-24
Input signal to TA4OUT pin
<Normal processing>
Countup is performed at the rising edges
input to the TAkIN pin when the TAkIN and
TAkOUT have the relationship that the TAkIN
pin’s input signal goes from “L” to “H” while
the TAkOUT (k = 2 and 3) pin’s input signal
is at “H” level.
Countdown is performed at the falling edges
input to the TAkIN pin when the TAkIN and
TAkOUT have the relationship that the TAkIN
pin’s input signal goes from “H” to “L” while
the TAkOUT pin’s input signal is “H.” (See
Figure 9.4.7.)
<Quadruple processing>
Countup is performed at all rising and fall-
ing edges input to the TA4OUT and TA4IN
pins when the TAkIN and TAkOUT have the
relationship that the TA4IN pin’s input signal
level goes from “L” to “H” while the TA4OUT
pin’s input signal is at “H” level.
Countdown is performed at all rising and
falling edges input to the TA4OUT and TA4IN
pins when the TAkIN and TAkOUT have the
relationship that the TA4IN pin’s input signal
level goes from “H” to “L” while the TA4OUT
pin’s input signal is at “H” level. (See Figure
9.4.8.)
Table 9.4.3 lists the input signals on the
TA4OUT and TA4IN
processing is selected.
Fig. 9.4.7 Normal processing
Table 9.4.3 TA4OUT and TA4IN pin’s input signals when quadruple processing is selected
“H” level
“L” level
Rising edge
Falling edge
“H” level
“L” level
Rising edge
Falling edge
Rising edge
Falling edge
“L” level
“H” level
Falling edge
Rising edge
“H” level
“L” level
Countup
Countdown
Fig. 9.4.8 Quadruple processing
Input signal to TA4IN pin
9.4 Event counter mode
TA4OUT
TA4IN
“H”
“L”
+1
Counted up at all edges.
–1
Counted down at all edges.
Counted up at all edges.
Counted down at all edges.
TAkOUT
TAkIN
(k=2, 3)
“H”
“L”
+1
–1
“L”
Countup
Countdown Countdown
Countdown