7906 datasheet(140/531 Pages) RENESAS

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TIMER A

7906 Group User’s Manual Rev.2.0

7-37

[Precautions for one-shot pulse mode]

1. Each of timers A3, A5 to A8 is not equipped with the one-shot pulse mode.

2. If the count start bit is cleared to “0” during counting, the counter becomes as follows:

•The counter stops counting, and the reload register’s contents are reloaded into the counter.

•The TAjOUT pin’s output level becomes “L.”

•The timer Aj interrupt request bit is set to “1.”

3. A one-shot pulse is output synchronously with an internally generated count source. Accordingly, when

selecting an external trigger, there will be a delay equivalent to one cycle of the count source at

maximum, in a period from when a trigger is input to the TAjIN pin until a one-shot pulse is output.

Fig. 7.5.6 Output delay in one-shot pulse output

4. When the timer’s operating mode has been set by one of the following procedures, the timer Aj interrupt

request bit will be set to “1.”

qWhen the one-shot pulse mode is selected after reset

qWhen the operating mode is switched from the timer mode to the one-shot pulse mode

qWhen the operating mode is switched from the event counter mode to the one-shot pulse mode

Accordingly, when using a timer Aj interrupt (interrupt request bit), be sure to clear the timer Aj interrupt

request bit to “0” after the above setting.

Note: The above applies when an external trigger (falling edge of TAjIN pin’s input signal) is selected.

TAjIN pin’s

input signal

Count

source

Trigger input

Starts outputting of one-shot pulse

One-shot pulse

output from

TAjOUT pin

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