HD404328U View Datasheet(PDF) - Hitachi -> Renesas Electronics

Part Name

Description

Manufacturer

HD404328U

4-Bit Microcontroller

Hitachi -> Renesas Electronics 

HD404328 Series

• 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 19. 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 20, 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

INT0

Sampling

High

Low

Low

Figure 19 Edge Detection

INT0

Interrupt

frame

A: Low

B: Low

a. High level period

Interrupt

frame

A: High

B: High

b. Low level period

Figure 20 Sampling Example

36

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