M16C62_M Datasheet, PDF (331/615 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
2.2.3 Operation of Timer A (timer mode, gate function selected)
In timer mode, choose functions from those listed in Table 2.2.2. Operations of the circled items are
described below. Figure 2.2.8 shows the operation timing, and Figure 2.2.9 shows the set-up procedure.
Table 2.2.2. Choosed functions
Item
Set-up
Count source
O Internal count source(f1 / f8 / f32 / fc32)
Pulse output function O No pulses output
Gate function
Pulses output
No gate function
Performs count only for the period in which the TAiIN pin is at “L” level
O Performs count only for the period in which the TAiIN pin is at “H” level
Operation (1) When the count start flag is set to “1” and the TAiIN pin inputs at “H” level, the counter per-
forms a down count on the count source.
(2) When the TAiIN pin inputs at “L” level, the counter holds its value and stops.
(3) If an underflow occurs, the content of the reload register is reloaded and the count continues.
At this time, the timer Ai interrupt request bit goes to “1”.
(4) Setting the count start flag to “0” causes the counter to hold its value and to stop.
Note
• Make the pulse width of the signal input to the TAiIN pin not less than two cycles of the count
source.
n = reload register content
FFFF16
(1) Start count
n
(2) Stop count
(3) Underflow
(4) Stop count
000016
Set to “1” by software
Count start flag ^{“1”}
“0”
TAiIN pin
“H”
input signal
“L”
Timer Ai interrupt “1”
request bit
“0”
Cleared to “0” by
software
Start count again.
Time
Set to “1” by software
Cleared to “0” when interrupt request is accepted, or cleared by software
Figure 2.2.8. Operation timing of timer mode, gate function selected
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