M16C62_N Datasheet, PDF (315/621 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY

Timer A
Mitsubishi microcomputers
M16C / 62 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2.2.9 Operation of Timer A (one-shot timer mode)
In one-shot timer mode, choose functions from those listed in Table 2.2.9. Operations of the circled items
are described below. Figure 2.2.20 shows the operation timing, and Figure 2.2.21 shows the set-up
procedure.
Table 2.2.9. Choosed functions
Item
Set-up
Count source
O Internal count source (f1 / f8 / f32 / fc32)
Pulse output function
No pulses output
O Pulses output
Count start condition
External trigger input (falling edge of input signal to the TAiIN pin)
External trigger input (rising edge of input signal to the TAiIN pin)
Timer overflow (TB2/TAj/TAk overflow)
O Writing “1” to the one-shot start flag
Note: j = i – 1, but j = 4 when i = 0; k = i + 1, but k = 0 when i = 4.
Operation (1) Setting the one-shot start flag to “1” with the count start flag set to “1” causes the counter to
perform a down count on the count source. At this time, the TAiOUT pin outputs an “H” level.
(2) The instant the value of the counter becomes “000016”, the TAiOUT pin outputs an “L” level,
and the counter reloads the content of the reload register and stops counting. At this time, the
timer Ai interrupt request bit goes to “1”.
(3) If a trigger occurs while a count is in progress, the counter reloads the value in the reload
register again and continues counting. The reload timing is in step with the next count source
input after the trigger.
(4) Setting the count start flag to “0” causes the counter to stop and to reload the content of the
reload register. Also, the TAiOUT pin outputs an “L” level. At this time, the timer Ai interrupt
request bit goes to “1”.
n = reload register content
FFFF16
(1) Start count
n
(2) Stop count
(3) Start count
Reload
Start count ^{(4) Stop count}
Reload
Reload
000116
Count start flag
“1”
“0”
Write signal to
one-shot start flag
One-shot pulse output “H”
from TAiOUT pin
“L”
Timer Ai interrupt
“1”
request bit
“0”
Set to “1” by software
1 / fi X (n)
Cleared to “0” by software
Time
1 / fi X (n+1)
Cleared to “0” when interrupt request is accepted, or cleared by software
Figure 2.2.20. Operation timing of one-shot mode
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