HD404829R Datasheet, PDF (43/149 Pages) Renesas Technology Corp – AS Microcomputer Incorporating a LCD controller/Driver Circuit

HD404829R Series
Notes: 2. When the MCU is in watch mode or subactive mode, if the high level period before the falling
edge of INT₀ is shorter than the interrupt frame, INT₀ is not detected. Also, if the low level period
after the falling edge of INT₀ is shorter than the interrupt frame, INT₀ is not detected.
Edge detection is shown in figure 24. The level of the INT₀ signal is sampled by a sampling
clock. When this sampled value changes to low from high, a falling edge is detected.
In figure 25, the level of the INT₀ signal is sampled by an interrupt frame. In (a) the sampled
value is low at point A, and also low at point B. Therefore, a falling edge is not detected. In (b),
the sampled value is high at point A, and also high at point B. A falling edge is not detected in
this case either.
When the MCU is in watch mode or subactive mode, keep the high level and low level period of
INT₀ longer than interrupt frame.
INT₀
Sampling
High
Low
Low
Figure 24 Edge Detection
INT₀
INT₀
Interrupt
frame
A: Low
B: Low
Interrupt
frame
A: High
B: High
(a) High level period
Figure 25 Sampling Example
(b) Low level period
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