Operation; Timer Mode - Renesas M16C Series User Manual

M30240 Group

2.3.2 Operation

2.3.2.1 Timer mode

In timer mode, select functions from those listed in Table 2.13 . An example using the indicated options
is described below. Figure 2.36 shows the operation timing, and Figure 2.37 shows the set-up
procedure.
Table 2.13: Timer B timer mode functions
Item
Count source O
Operation
(1) Setting the count start flag to "1" causes the counter to perform a down count on the count source.
(2) If an underflow occurs, the content of the reload register is reloaded, and the counter continues
counting. At this time, the Timer Bi interrupt request bit goes to "1".
(3) Setting the count start flag to "0" causes the counter to hold its value and to stop.
FFFF
0000
"1"
Count start flag
"0"
Timer Bi interrupt
"1"
request bit
"0"
Figure 2.36: Operation timing of timer mode
Rev.1.00 Sep 24, 2003 Page 174 of 360
Internal count source (f1/f8/f32)
n = reload register content
(1) Start count (2) Underflow
16
n
16
Set to "1" by software
Cleared to "0" when interrupt request is accepted, or cleared by software
Set-up
(3) Stop count
Start count
again
Cleared to "0" by
Set to "1" by software
software
Timer B
Time