Specifications

©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
146
Application Notes for Host designers
1)
Once enabling Power Sustenance, Host shall use Power Off Notification sequence to shut
down card power. Card power supply control by monitoring open/close the slot cover is one
of possible safe solutions while in Power Sustenance to avoid sudden card removal.
2) In addition, card-
internal program or erase procedures may continue during Power
Sustenance mode even if card is locked by CMD42
. If Host is to shut down card power in
this situation, Host shall unlock the card at first and execute Power Off Notification
sequence as mentioned above.
3)
While Power Sustenance is enabled, card may consume power for internal operations, even
wit
hout Host. So Host who would like to save power while card is unused, should disable
Power Sustenance mode.
4) During Power Sustenance Mode, card may access to memory internally.
5) Assume power consumption during Power Sustenance mode is equivalent to that of normal
command operation. Setting of Power Limit through CMD6
, is effective even in Power
Sustenance mode.
6)
By enabling Power Sustenance mode, total performance of Card may be noticeably
improved. The actual level of improvement is not specified by the physi
cal spec, and
depends on the card’s implementation.
5.8.1.5 Power Down Mode
This function can be used in SD mode only. In UHS-II mode, Hibernate mode should be used. Always
PDMR=0 in UHS-II mode. In Power Down Mode, card executes at least CMD48/49 for exiting from
Power Down Mode and CMD0. If host set PDMN to 1, card should set PDMR to 1 within 1 second of
CMD49 busy period. If PDMR cannot be set to 1 within busy period, card shall set PDMR to 1 within 1
second from end of busy of CMD49. If host set PDMN to 0, card should set PDMR to 0 within 1 second
of CMD49 busy period. If PDMR cannot be set to 0 within busy period, card shall set PDMR to 0 within
1 second from end of busy of CMD49. The card states retrieved from Power Down Mode is same as
that before entering Power Down Mode.
• Entering Power Down Mode
(1) Host checks support bit of Power Down Mode. If PDMS=1, host may use Power Down Mode.
(2) Host sets PDMN to 1.
(3) Host waits until busy of CMD49 is released.
(4) Host polls Power Management Status register until the card indicates PDMR=1.
(5) Host keeps providing VDD. SD Clock should be stopped.
• Exiting Power Down Mode
(1) Host starts to provide SD Clock.
(2) Host sets PDMN=0 in the Power Management Setting Register if PDMR=1.
(3) Host waits until busy of CMD49 is released.
(4) Host polls Power Management Status register until the card indicates PDMR=0.
• Aborting Power Down Mode
(1) If CMD0 is received, the card exits Power Down Mode and enters idle state.
(2) Initialization is required to use the card.