m5m51016btp Renesas Electronics Corporation., m5m51016btp Datasheet - Page 29

• Manufacturer Part Number: m5m51016btp
• Description: Renesas 16-bit Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

M30245 Group
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
Operation
Figure 2.2.14. Operation timing of event counter mode, free run type selected
2.2.6 Operation of Timer A (event counter mode, free run type selected)
Count start flag
Timer Ai interrupt
request bit
Up/down flag
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.
Note: First set to “Reload type” operation. Once the first counting pulse has occurred, the timer may be changed to “Free-Run type”.
Table 2.2.5. Choosed functions
Note: j = i – 1, but j = 4 when i = 0
(1) Setting the count start flag to “1” causes the counter to count the falling edges of the count
(2) Even if an underflow occurs, the content of the reload register is not reloaded, but the count
(3) If switching from an up count to a down count or vice versa while a count is in progress, the
(4) Even if an overflow occurs, the content of the reload register is not reloaded, but the count
FFFF
0000
Count source
source.
continues. At this time, the timer Ai interrupt request bit goes to “1”.
switch takes effect from the next effective edge of the count source.
continues. At this time, the timer Ai interrupt request bit goes to “1”.
“1”
“0”
“1”
“0”
“1”
“0”
16
16
n
(Note)
n = reload register content
Item
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(1) Start count
Set to “1” by software
O
(2) Underflow
TAj overflow
Input signal to TAi
(counting falling edges)
Input signal to TAi
(counting rising edges)
Cleared to “0” when interrupt request is accepted, or cleared by software
Set-up
IN
IN
Count operation type
Factor for switching
between up and
down
Pulse output function
(3) Switch count
Set to “1” by software
Item
O
O
O
Reload type
Free-run type
Content of up/down flag
Input signal to TAi
No pulses output
Pulses output
Set-up
(4)
Overflow
Time
OUT
2. Timer A