C541U_99 Datasheet, PDF (165/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

Power Saving Modes
C541U
Special Function Register PCON (Address 87H)
Special Function Register PCON1 (Mapped Address 88H)
Bit No. MSB
7
6
5
4
3
2
87H
–
PDS IDLS
–
GF1 GF0
Reset Value : X00X0000B
Reset Value : 0XX0XXXXB
1
PDE
LSB
0
IDLE PCON
88H EWPD –
–
WS
–
–
–
– PCON1
Symbol
PDS
IDLS
GF1
GF0
PDE
IDLE
EWPD
WS
–
The function of the shaded bit is not described in this section.
Function
Power down start bit
The instruction that sets the PDS flag bit is the last instruction before entering
the power down mode
Idle start bit
The instruction that sets the IDLS flag bit is the last instruction before entering
the idle mode.
General purpose flag
General purpose flag
Power down enable bit
When set, starting of the power down is enabled
Idle mode enable bit
When set, starting of the idle mode is enabled
External wake-up from powe down enable bit
Setting EWPD before entering power down mode, enables the external wake-
up from power down mode capability via the pin P3.2/INT0 or by the USB
module.
Wake-up from software power down mode source select
WS = 0 : wake-up via pin P3.2/INT0 selected (default after reset)
WS = 1 : wake-up via USB bus selected
Reserved bits for future use.
Semiconductor Group
9-2
1997-10-01