4571 Datasheet, PDF (45/126 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

4571 Group
(4) Return signal
An external wakeup signal is used to return from the RAM back-
up mode because the oscillation is stopped. Table 20 shows the
return condition for each return source.
(5) Control registers
• Key-on wakeup control register K0
Register K0 controls the port P0 key-on wakeup function. 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.
• Key-on wakeup control register K1
Register K1 controls the port P1 key-on wakeup function. Set
the contents of this register through register A with the TK1A
instruction. In addition, the TAK1 instruction can be used to
transfer the contents of register K1 to register A.
• Key-on wakeup control register K2
Register K2 controls the ports K and P2 key-on wakeup
function. Set the contents of this register through register A
with the TK2A instruction. In addition, the TAK2 instruction
can be used to transfer the contents of register K2 to register A.
• Key-on wakeup control register L1
Register L1 controls the selection of the selection of the INT0
pin return condition and INT0 pin key-on wakeup function and
the selection of the INT1 pin return condition and INT1 pin
key-on wakeup function. Set the contents of this register
through register A with the TL1A instruction. In addition, the
TAL1 instruction can be used to transfer the contents of
register L1 to register A.
• Pull-up control register PU0
Register PU0 controls the ON/OFF of the port P0 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.
• Pull-up control register PU1
Register PU1 controls the ON/OFF of the port P1 pull-up
transistor. Set the contents of this register through register A
with the TPU1A instruction. In addition, the TAPU1
instruction can be used to transfer the contents of register PU1
to register A.
• Pull-up control register PU2
Register PU2 controls the ON/OFF of the ports P2 pull-up
transistor. Set the contents of this register through register A
with the TPU2A instruction. In addition, the TAPU2
instruction can be used to transfer the contents of register PU2
to register A.
• Interrupt control register I1
Register I1 controls the valid waveform/level of the INT0 pin
and the input control of INT0 pin. Set the contents of this
register through register A with the TI1A instruction. In
addition, the TAI1 instruction can be used to transfer the
contents of register I1 to register A.
Table 20 Return source and return condition
Return source
Port P00−P03
Port P10−P13
Port P20, P21
Port K
INT pin
Return condition
Return by an external falling edge (“H” → “L”)
input.
Return by an external “H” level or “L” level input,
or falling edge (“H” → “L”) or rising edge (“L” →
“H”).
When the return level is input, the EXF0 flag is
not set.
Remarks
The key-on wakeup function can be selected by
one port unit. Set the port using the key-on
wakeup function to “H” level before going into
the RAM back-up state.
The key-on wakeup function can be selected by
one port unit. Select the return level (“L” level or
“H” level) with the register I1 and return condition
(level or edge) with the register L1 according to
the external state before going into the RAM
back-up state.
Rev.1.02 May 25, 2007 Page 45 of 124
REJ03B0179-0102