7477 datasheet(185/354 Pages) RENESAS

185 / 354 page

7470/7471/7477/7478 GROUP USER’S MANUAL

1-168

HARDWARE

1.17 Low-power dissipation function

2 Recovery by interrupt

In the wait mode, oscillation is continued. Accordingly, as soon as the wait mode is released, an

instruction is executed.

When an interrupt request is generated in the wait mode, this wait mode is released and the supply

of internal clock

φ to the CPU is started. At the same time, the interrupt request used for recovery

is accepted, so that the interrupt processing routine is executed.

The interrupt sources that are available for recovery are shown below.

q INT0, INT1

q CNTR0, CNTR1

q Serial I/O

q A-D conversion

q Timer 1 to timer 4

q Key input (key on wake up)

However, when the above interrupt sources are used for recovery from the wait mode, perform the

following setting and then execute the WIT instruction to permit an interrupt to be used.

[Register setting]

1 Clear the interrupt request bit of the interrupt source to be used for recovery to “0.”(No request)

2 Set the interrupt enable bit of the interrupt source to be used for recovery to “1.”(Enabled)

3 Clear the interrupt disable flag I to “0.” (Enabled)

For the details of the Interrupt, refer to “1.11 Interrupts.”

7477 Datasheet(PDF) 185 Page - Renesas Technology Corp