TIMER A
7.5 One-shot pulse mode
7.5.2 Trigger
The counter is enabled for counting when the count start bit (addresses 4016, 4116) has been set to “1.” The
counter starts counting when a trigger is generated after counting has been enabled. An internal or external
trigger can be selected as that trigger.
An internal trigger is selected when the trigger select bits (bits 4 and 3 at addresses 5616 to 5816, 5A16, DA16
are “00 ” or “01 ”; an external trigger is selected when the bits are “10 ” or “11 .”
)
2
2
2
2
If a trigger is generated during counting, the reload register’s contents are reloaded and the counter
continues counting. If a trigger generated during counting, make sure that a certain time which is equivalent
to one cycle of the timer’s count source or more has passed between the previously trigger occurrence and
a new trigger occurrence.
(1) When selecting internal trigger
A trigger is generated when writing “1” to the one-shot start bit (addresses 4216, 4316). Figure 7.5.4
shows the structures of the one-shot start registers 0 and 1.
(2) When selecting external trigger
A trigger is generated at the falling edge of the TAjIN pin’s input signal when bit 3 at addresses 5616
to 5816, 5A16, DA16 is “0,” or at its rising edge when bit 3 is “1.”
When using an external trigger, set the port P2 and port P6 direction registers’ bits which correspond
to the TAjIN pins for the input mode.
7906 Group User’s Manual Rev.2.0
7-33
RENESAS [ RENESAS TECHNOLOGY CORP ]
