Specifications

©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
144
Figure 5-18 : Power Management Setting Register
5.8.1.3 Power Off Notification
Figure 5-19 shows flow chart to control Power Off Notification Sequence. Card should set POFR to 1
within 1 second of CMD49 busy period. If POFR cannot be set to 1 within busy period, card shall set
POFR to 1 within 1 second from end of busy of CMD49.
Figure 5-19 : Power Off Notification Flow
• Power Off Notification Sequence
(1) Host checks support bit of Power Off Notification. If POFS=1, host may use Power Off Notification.
(2) Just before host would like to shut down card power, host requests Power Off Notification to the
card by setting POFN=1.
(3) Host waits until busy of CMD49 is released.
(4) Host polls Power Management Status register until the card indicates ready to power off
Bit Position 7 6 5 4 3 2 1 0
Field Name Rsv Rsv Rsv Rsv Rsv PDMN PSUN POFN
Value 0 0 0 0 0 x x x
Power Off Notification
0: Normal Operation
1: Power Off Request
Power Sustenance Notification
0: Host may not support Power Off Notification
1: Host uses Power Off Notification to shut down power
Power Down Mode Notification
0: Normal Operation
1: Power Down Request
If PDMS=1, this bit may be set to 1.
Setting this bit lets a card go into Power Down Mode.
Clearing this bit retrieves the card from Power Down
Mode without re-initialization.
If POFS=1, this bit may be set to 1.
After setting POFN=1, host may use only CMD48 to
poll Power Management Status register.
If PSUS=1, this bit may be set to 1.
PSUN=1 means that host is accepted to sustain power supply
to the card as much as possible.
Once PSUN=1, the host needs to set PSUN=0 and POFN=1
and wait until POFR=1 to shut down card power.
CMD48 Read POFS
Base + 1
Check POFS
CMD49 Set POFN=1
Base + 2
Check POFR
CMD48 Read POFR
Base + 1
POFS=0
POFR=0
POFR=1
Host is going to shut down the card power
Start
Wait during Busy
POFS=1
End
Shut Down Card Power