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PRELIMINARY
S3C6400X RISC MICROPROCESSOR
HSMMC CONTROLLER
27-7
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
(5) Judge whether SD Bus voltage must be changed or not. If SD Bus voltage must be changed, go to step (6). If
SD Bus voltage does not to be changed, go to ‘End’.
(6) Set SD Bus Power in the Power Control register to 0 for clearing this bit. The card requires voltage rising from
0 volt to detect it correctly. The Host Driver shall clear SD Bus Power before changing voltage by setting SD Bus
Voltage Select.
(7) Set SD Bus Voltage Select in the Power Control register.
(8) Set SD Bus Power in the Power Control register to 1.
Note:
Step (2) and step (3) can be executed at same time. Also, step (7) and step (8) can be executed at same
time.
CHANGE BUS WIDTH SEQUENCE
Disable Card Interrupt in Host
(1)
START
SD Memory Only
Card ?
(2)
Mask Card Interrupt in Card
(3)
Change Bit Mode in Card
(4)
Change Bit Mode for Host
(5)
SD Memory Only
Card ?
(6)
Enable Card Interrupt in Card
(7)
Enable Card Interrupt in Host
(8)
yes
no
yes
no
END
Figure 27-7. Change Bus Width Sequence
The sequence for changing bit mode on SD Bus is shown in Figure 27-7.
(1) Set Card Interrupt Status Enable in the Normal Interrupt Status Enable register to 0 for masking incorrect
interrupts that may occur while changing the bus width.
(2) In case of SD memory card, go to step (4). In case of other card, go to step (3).
(3) Set “IENM” of the CCCR in a SDIO or SD combo card to 0 by CMD52.