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14.1.3
One-Shot Timer Mode
When a trigger occurs, the timer decrements the counter until underflows. Then, the counter is reloaded and
stops until the next trigger occurs.
one-shot timer mode, and
Figure 14.16 shows a one-shot timer mode operation.
Table 14.6
Specifications of One-Shot Timer Mode
NOTES:
1. Bits CNT3 to CNT0 in the TCSPR register select no division (n = 0) or divide-by-2n (n = 1 to 15).
2. Wait for 1 count source cycle or more to write after the count starts.
Item
Specification
Count sources
Count operations
Timer decrements a counter value
When the timer reaches 0000h, it stops counting after reloading until the next
trigger occurs.
If a trigger occurs while counting, the contents of the reload register are
reloaded into the counter and the count continues.
Number of Count times
n times
n: setting value of the TAi register (i = 0 to 4), 0000h to FFFFh
(but the counter does not run if n = 0000h)
Count start condition
A trigger, selectable from the following occurs while the TAiS bit in the TABSR
register is set to 1 (count starts):
the TAiOS bit in the ONSF register is set to 1 (timer starts)
an external trigger is applied to TAiIN pin
timer B2 overflows or underflows,
timer Aj overflows or underflows (j = i - 1, except j = 4 if i = 0),
timer Ak overflows or underflows (k = i + 1, except k = 0 if i = 4)
Count stop condition
After the counter has reached 0000h and the counter value is reloaded
When the TAiS bit is set to 0 (timer stops)
Interrupt request generation timing When the counter reaches 0000h
TAiIN pin function
Trigger input
TAiOUT pin function
Pulse output
Read from timer
The TAi register cannot be read
Write to timer
When a value is written to the TAi register while the count is stopped, the value
is written to both the reload register and the counter.
When a value is written to the TAi register while counting, the value is written to
the reload register (It is transferred to the counter at the next reload timing)
.(2)