TIMER A
7.3 Timer mode
7.3 Timer mode
In this mode, the timer counts an internally generated count source. Table 7.3.1 lists the specifications of
the timer mode. Figure 7.3.1 shows the structures of the timer Ai register and timer Ai mode register in the
timer mode.
Table 7.3.1 Specifications of timer mode
Item
Count source f
i
Count operation
f
1
, f
2
, f
16
, f
64
, f
512
, or f
4096
• Countdown
• When a counter underflow occurs, reload register’s contents are
reloaded, and counting continues.
Division ratio
Count start condition
Count stop condition
Interrupt request occurrence timing
TAj
IN
pin function
TAj
OUT
pin function
Read from timer Ai register
Write to timer Ai register
1
(n + 1)
n : Timer Ai register setting value
Specifications
When count start bit is set to “1.”
When count start bit is cleared to “0.”
When a counter underflow occurs.
Programmable I/O port pin or gate input pin
Programmable I/O port pin or pulse output pin
Counter value can be read out.
q
While counting is stopped
When a value is written to the timer Ai register, it is written to both
reload register and counter.
q
While counting is in progress
When a value is written to the timer Ai register, it is written to only
reload register. (Transferred to the counter at the next reload timing.)
Note:
Only timer Aj (j = 0 to 2, 4, 9) is equipped with the I/O pins.
7906 Group User’s Manual Rev.2.0
7-11
RENESAS [ RENESAS TECHNOLOGY CORP ]
