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27. Usage Notes
Rev.1.00
27.9.2.3
Timer A (One-Shot Timer Mode)
The TAiS bit (i = 0 to 4) in the TABSR register is set to 0 (count stops) after reset. Set the TAiS bit to 1
(count starts) after selecting operating mode and setting the TAi register.
The following occurs when the TAiS bit in the TABSR register is set to 0 (count stops) while counting.
The counter stops counting and the contents of the reload register is reloaded.
The TAiOUT pin outputs a low-level (“L”) signal.
The IR bit in the TAiIC register becomes 1 (interrupt requested) after one BCLK clock.
One-shot timer is operated with an internal count source. When an external trigger is selected, a maximum
of one count source clock delay occurs between the trigger input to the TAiIN pin and the one-shot timer
output.
The IR bit becomes 1 when one of the following procedures are used to set timer’s operating mode.
When selecting one-shot timer mode after reset.
When switching from timer mode to one-shot timer mode.
When switching from event counter mode to one-shot timer mode.
To use the timer Ai interrupt (IR bit), set the IR bit to 0 after one of the above setting has done.
When a retrigger occurs while counting, the contents of the reload register is reloaded after the counter
decrements by one, and continues counting.
To generate a retrigger while counting, wait 1 count source clock or more from the last trigger.
When an external trigger input is selected to start counting in timer A one-shot timer mode, do not provide
an external retrigger input for 300 ns before a timer A counter value reaches 0000h. One-shot timer may
stop counting.
(Technical update: TN-16C-125A/EA)
27.9.2.4
Timer A (Pulse Width Modulation Mode)
The TAiS bit (i = 0 to 4) in the TABSR register is set to 0 (count stops) after reset. Set the TAiS bit to 1
(count starts) after selecting operating mode and setting the TAi register.
The IR bit becomes 1 when one of the following procedures are used to select timer’s operating mode.
When selecting PWM mode after reset.
When switching from timer mode to PWM mode.
When switching from event counter mode to PWM mode.
To use the timer Ai interrupt (IR bit), set the IR bit to 0 after one of the above setting has done.
The following occurs when the TAiS bit is set to 0 (count stops) while PWM pulse is output.
The counter stops.
When the TAiOUT pin outputs a high-level (“H”) signal, its output signal changes to “L” and the IR bit
becomes 1.
When the TAiOUT pin outputs an “L” signal, its output signal and the IR bit remains unchanged.