M16C62_M Datasheet, PDF (339/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

Timer A
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2.2.7 Operation of timer A (2-phase pulse signal process in event counter mode,
normal mode selected)
In processing 2-phase pulse signals in event counter mode, choose functions from those listed in Table
2.2.6. Operations of the circled items are described below. Figure 2.2.16 shows the operation timing, and
Figure 2.2.17 shows the set-up procedure.
Table 2.2.6. Choosed functions
Item
Set-up
Count operation type
Reload type
O Free run type
2-phase pulses
process (Note)
O Normal processing
4-multiplication processing
Note: Timer A3 alone can be selected. Timer A2 is solely used for normal processes, and timer A4 is solely used 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
continues. At this time, the timer Ai interrupt request bit goes to “1”.
(3) Even if an overflow occurs, the content of the reload register is not reloaded, but the count
continues. At this time, the timer Ai interrupt request bit goes to “1”.
Note
• The up count or down count conditions are as follows:
If a rising edge is present at the TAiIN pin when the input signal level to the TAiOUT pin is “H”,
an up count is performed.
If a falling edge is present at the TAiIN pin when the input signal level to the TAiOUT pin is “H”,
a down count is performed.
“H”
TAiOUT
“L”
TAiIN ^{“H”}
“L”
(1) Start count
FFFF16
(2) Underflow
(3) Overflow
000016
Count start flag ^{“1”}
“0”
Timer Ai interrupt ^{“1”}
request bit
“0”
Set to “1” by software
Time
Cleared to “0” when interrupt request is accepted, or cleared by software
Figure 2.2.16. Operation timing of 2-phase pulse signal process in event counter mode, normal mode selected
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