4524_M Datasheet, PDF (242/310 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 720 FAMILY / 4500 SERIES

4524 Group
APPLICATION
2.9 Power down
2.9.1 Power down mode
The system goes into power down mode when the POF or POF2 instruction is executed immediately after
the EPOF instruction is executed. Table 2.9.1 shows the function and state retained at power down mode.
Also, Table 2.9.2 shows the return source from this state.
(1) Clock operating mode
The system goes into clock operating mode when the POF instruction is executed immediately after
the EPOF instruction is executed.
As main clock oscillation (XIN-XOUT) and system clock stop with RAM, the state of reset circuit, sub-
clock oscillation circuit (XCIN-XCOUT), LCD display and timer 5 retained, current dissipation can be
reduced.
(2) RAM back-up mode
The system goes into RAM back-up mode when the POF2 instruction is executed immediately after
the EPOF instruction is executed.
As oscillation stops with RAM and the state of reset circuit retained, current dissipation can be
reduced without losing the contents of RAM.
Rev.2.00 Aug, 06 2004
REJ09B0107-0200Z
2-78