TIMER A
7.5 One-shot pulse mode
7.5 One-shot pulse mode
In this mode, the timer outputs a pulse which has an arbitrary width once.
When a trigger occurs, the timer outputs “H” level from the TAiOUT pin for an arbitrary time. Table 7.5.1 lists
the specifications of the one-shot pulse mode. Figure 7.5.1 shows the structures of the timer Ai register and
timer Ai mode register in the one-shot pulse mode.
Table 7.5.1 Specifications of one-shot pulse mode
Item
Specifications
Count source f
i
f
1
, f
2
, f16, f64, f512, or f4096
Count operation
ꢀ Countdown
ꢀ When the counter value becomes “000016,” reload register’s con-
tents are reloaded, and counting stops.
ꢀ If a trigger occurs during counting, reload register’s contents are
reloaded, and counting continues.
Output pulse width (“H”)
Count start condition
Count stop condition
n
[s] n : Timer Ai register’s set value
f
i
ꢀ When a trigger occurs. (Note)
ꢀ Internal or external trigger can be selected by software.
ꢀ When the counter value becomes “000016
ꢀ When the count start bit is cleared to “0”
When counting stops.
”
Interrupt request occurrence timing
TAiIN pin’s function
Programmable I/O port pin or trigger input pin
One-shot pulse output
TAiOUT pin’s function
Read from timer Ai register
Write to timer Ai register
An undefined value is read out.
ꢀ While counting is stopped
When a value is written to timer Ai register, it is written to both of
the reload register and counter.
ꢀ While counting is in progress
When a value is written to timer Ai register, it is written only to the
reload register. (Transferred to counter at the next reload timing.)
Note: The trigger is generated with the count start bit = “1.”
7905 Group User’s Manual Rev.1.0
7-29
RENESAS [ RENESAS TECHNOLOGY CORP ]
