7702 datasheet(85/217 Pages) RENESAS

85 / 217 page

7702/7703 Group User’s Manual

INTERRUPTS

4–23

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4.10.1 Function of INTi interrupt request bit

(1)

Selecting edge sense mode

The interrupt request bit has the same function as that of internal interrupts. That is, when an

interrupt request occurs, the interrupt request bit is set to “1.” The bit remains set to “1” until the

interrupt request is accepted; it is cleared to “0” when the interrupt request is accepted. By software,

this bit also can be set to “0” in order to clear the interrupt request or “1” in order to generate the

interrupt request.

(2)

Selecting level sense mode

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The INTi interrupt request bit becomes ignored.

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In this case, the interrupt request occurs continuously while the level of the INTi pin is valid level

V1.

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When the INTi pin level changes from the valid level to the invalid level

V2 before the INTi interrupt

request is accepted, this interrupt request is not retained. (Refer to Figure 4.10.4.)

Valid levelV1: This means the level which is selected by the polarity select bit (bit 4 at addresses 7D16

to 7F16).

Invalid levelV2: This means the reversed level of a valid level.

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4.10 External interrupts (INTi interrupt)

INTi pin

Edge detection

circuit

Interrupt request

Level sense/Edge sense

select bit

Data bus

Interrupt request bit

“0”

“1”

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Fig. 4.10.3 Circuit of INTi Interrupt

7702 Datasheet(PDF) 85 Page - Renesas Technology Corp