Renesas 4513 Manual Do Utilizador

1-54

4513/4514 Group User’s Manual

An external wakeup signal is used to return from the RAM back-up

mode because the oscillation is stopped. Table 21 shows the return

condition for each return source.

• Key-on wakeup control register K0

Register K0 controls the ports P0 and P1 key-on wakeup func-

tion. Set the contents of this register through register A with the

TK0A instruction. In addition, the TAK0 instruction can be used to

transfer the contents of register K0 to register A.

• Pull-up control register PU0

Register PU0 controls the ON/OFF of the ports P0 and P1 pull-up

transistor. Set the contents of this register through register A with

the TPU0A instruction. In addition, the TAPU0 instruction can be

used to transfer the contents of register PU0 to register A.

Remarks

Set the port using the key-on wakeup function selected with register K0 to
“H” level before going into the RAM back-up state because the port P0
shares the falling edge detection circuit with port P1.

Select the return level (“L” level or “H” level) with the bit 2 of register I1 ac-
cording to the external state before going into the RAM back-up state.

Select the return level (“L” level or “H” level) with the bit 2 of register I2 ac-
cording to the external state before going into the RAM back-up state.

Return condition

Return by an external falling
edge input (“H”

→

“L”).

Return by an external “H” level or
“L” level input.
The EXF0 flag is not set.

Return by an external “H” level or
“L” level input.
The EXF1 flag is not set.

External wakeup

signal

Return source

Ports P0, P1

Port P3

0

/INT0

Port P3

1

/INT1