Outline Of Each Mode Of Tio - Mitsubishi Electric M32R Series User Manual

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10.4.2

Outline of Each Mode of TIO

Each mode of TIO is outlined below. For each TIO channel, only one of the following modes can be
selected.
(1) Measure clear/free-run input modes
In measure clear/free-run input modes, the timer measures a duration of time from when it starts
counting till when an external capture signal is entered.
After the timer is enabled (by writing to the enable bit in software), the counter starts counting
down synchronously with the count clock. When a capture signal is entered from an external
device, the counter value at that point in time is written to a register called the "measure register."
Especially in measure clear input mode, the counter value is initialized to H'FFFF upon capture,
from which the counter starts counting down again. In measure free-run mode, the counter
continues counting down even after capture and upon underflow, recycles to H'FFFF, from which
it starts counting down again.
To stop the counter, disable count by writing to the enable bit in software. Note that an interrupt
can be generated by a counter underflow or execution of measure operation.
(2) Noise processing input mode
In noise processing input mode, the timer detects the status of an input signal that it remained in
the same state for over a predetermined time.
In noise processing input mode, the counter is started by entering a high or low-level signal from
an external device and if the signal remains in the same state for over a predetermined time
before the counter underflows, the counter stops after generating an interrupt. If the valid-level
signal being applied turns to an invalid level before the counter underflows, the counter
temporarily stops counting and when a valid-level signal is entered again, it is reloaded with the
initial count and restarts counting.
The timer stops at the same time the counter underflows or count is disabled by writing to the
enable bit. An interrupt can be generated by a counter underflow.
(3) PWM output mode (without correction function)
In PWM output mode, the timer uses two reload registers to generate a waveform with a given
duty cycle.
10.4 TIO (Input/Output-related 16-bit Timer)
10-102
MULTIJUNCTION TIMERS
Ver.0.10