MULTIJUNCTION TIMERS
10.4 TIO (Input/Output-Related 16-Bit Timer)
10
10.4.10 Operation in TIO Noise Processing Input Mode
In noise processing input mode, the timer is used to detect that the input signal remained in the same state for
over a predetermined time.
In noise processing input mode, a high or low level on external input activates the counter and if the input signal
remains in the same state for over a predetermined time before the counter underflows, the counter generates
an interrupt request before stopping. 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, the
counter is reloaded with the initial count and restarts counting. The effective count width is (reload 0 register set
value + 1).
The timer stops at the same time the counter underflows or count is disabled by writing to the enable bit. An
interrupt request can be generated by a counter underflow.
Enabled
(by writing to
the enable bit)
Count clock
Disabled by underflow
Enable bit
External input
(noise processing)
Invalid
Invalid
Effective signal
width
H'FFFF
H'A000
Counter
H'0000
Reload 0 register
H'A000
TIO interrupt request
TIO interrupt request due
to underflow
Note: • This diagram does not show detailed timing information.
Figure 10.4.8 Typical Operation in Noise Processing Input Mode
32180 Group User’s Manual (Rev.1.0)
10-116
RENESAS [ RENESAS TECHNOLOGY CORP ]
