M16C62_M Datasheet, PDF (337/615 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
2.2.6 Operation of Timer A (event counter mode, free run type selected)
In event counter mode, choose functions from those listed in Table 2.2.5. Operations of the circled items
are described below. Figure 2.2.14 shows the operation timing, and Figure 2.2.15 shows the set-up
procedure.
Table 2.2.5. Choosed functions
Item
Count source
Set-up
O
Input signal to TAiIN
(counting falling edges)
Input signal to TAiIN
(counting rising edges)
Timer overflow
(TB2/TAj overflow)
Item
Set-up
Pulse output function O
Count operation type
O
Factor for switching O
between up and
down
No pulses output
Pulses output
Reload type
Free-run type
Content of up/down flag
Input signal to TAiOUT
Note: j = i – 1, but j = 4 when i = 0
Operation (1) Setting the count start flag to “1” causes the counter to count the falling 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) If switching from an up count to a down count or vice versa while a count is in progress, the
switch takes effect from the next effective edge of the count source.
(4) 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”.
n = reload register content
(2) Underflow
FFFF16
(1) Start count
n
(3) Switch count
(4) Overflow
000016
“1”
Count start flag
“0”
“1”
Up/down flag
“0”
Timer Ai interrupt _{“1”}
request bit
“0”
Set to “1” by software
Time
Set to “1” by software
Cleared to “0” when interrupt request is accepted, or cleared by software
Figure 2.2.14. Operation timing of event counter mode, free run type selected
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