7540 datasheet(85/366 Pages) RENESAS

85 / 366 page

2-9

REJ09B0018-0200Z

Rev.2.00

Jun 21, 2004

7540 Group

APPLICATION

2.1 I/O port

Processing

Set pull-up control register, if necessary

PULL(Address 1616)

P00 pull-up On/Off

P01 pull-up On/Off

P02,P03 pull-up On/Off

P04–P07 pull-up On/Off

RTI

CLI

INTEDGE(Address 3A16)

RESET

SEI

CLD

CLT

CPUM(Address 3B16)

← 10000X002

Wait until f(XIN) oscillation is stabilized (Note 1)

CPUM(Address 3B16)

← XX000X002

Set port P0i using key-on wakeup interrupt to input mode.

Set port not using key-on wakeup interrupt to output mode.

Set interrupt edge selection register (Note 2)

Key-on wakeup enabled

Set “0” to the key-on wakeup interrupt request bit.

Initialization

Set “1” to the key-on wakeup interrupt enable bit.

(key-on wakeup interrupt enabled)

X: This bit is not used here. Set it to “0” or “1” arbitrary.

Notes 1: For the concrete time, ask the oscillator manufacture.

2: In this case, port P00 is used.

Key-on waleup interrupt processing routine

Processing

Fig. 2.1.13 Example of control procedure (2)

2.1.4 Application example of key-on wake up (2)

Outline: The key-on wakeup interrupt is used as the normal external interrupt.

Specifications: The key-on wakeup interrupt occurs by input of the falling edge to port P0i. If necessary,

the built-in pull-up resistor is used.

Note: Only the falling edge is active for the key-on wakeup interrupt.

Figure 2.1.13 shows an example of control procedure.

7540 Datasheet(PDF) 85 Page - Renesas Technology Corp

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