Renesas M16C Series User Manual

Timer A
M30240 Group
Rev.1.00 Sep 24, 2003 Page 159 of 360
2.2.2.7 2-phase pulse signal process in event counter mode with Multiply-by-4 mode selected
In processing 2-phase pulse signals in event counter mode, select functions from those listed in Table
2.7 . An example using the indicated options is described below. Figure 2.19 shows the operation timing
and Figure 2.20 shows the set-up procedure.
Table 2.7: Timer A 2-phase pulse signal process in event counter mode, multiply by 4 functions
Note: Only Timer A3 can select between normal and 4-multiplication processing.
Timer A2 is used only for normal processes.
Timer A4 is used only for 4-multiplication processes.
Operation
(1) Setting the count start flag to “1” causes the counter to count effective edges of the count source.
(2) Even if an underflow occurs, the content of the reload register is not reloaded, but the count con-
tinues. At this time, the interrupt request bit goes to “1”.
(3) Even if an overflow occurs, the content of the reload register is not reloaded, but the count contin-
ues. At this time, the interrupt request bit goes to “1”.
Note: The up count or down count conditions are shown in Table 2.8 .
Table 2.8: Up count or Down count conditions
Figure 2.19: Operation timing of 2-phase pulse signal process in event counter mode, multiply by 4
Item
Set-up Item Set-up
Count operation type
Reload type
Processing 2-phase
pulses (Note)
Normal processing
O Free-run type O 4-multiplication processing
Input signal to the
TAiOUT pin
Input signal to
the TAiIN pin
Input signal to the
TAiOUT pin
Input signal to the
TAiIN pin
Up count
“H” level Rising
Down count
“H” level Falling
“L” level Falling “L” level Rising
Rising “L” level Rising “H” level
Falling “H” level Falling “L” level
Time
Set to “1” by software
0000
16
Count start flag
Timer Ai interrupt
request bit
“1”
“0”
“1”
“0”
FFFF
16
Counter content (hex)
Input pulse
TA i OUT
“H”
“L”
“H”
“L”
TA i
IN
(1) Start count
(2) Underflow
(3) Overflow
Cleared to “0” when interrupt request is accepted, or cleared by software

Renesas M16C Series Specifications

General

Brand	Renesas
Model	M16C Series
Category	Computer Hardware
Language	English