Samsung S5PC110 Manual page 988

S5PC110_UM
7.4.6 CHANGE BUS WIDTH SEQUENCE
(1 )
Disable Card Interrupt in Host
(2)
(3 )
Mask Card Interrupt in Card
(4 )
(5 )
The sequence to change bit mode on SD Bus is shown in
1. To mask incorrect interrupts that may occur while changing the bus width, Set Card Interrupt Status Enable
(STACARDINT) in the Normal Interrupt Status Enable register to 0.
2. If SD memory card is used, go to step (4). In case of other card, go to step (3).
3. Use CMD52 to set "IENM" of the CCCR in a SDIO or SD combo card to 0.
4. Change the bit mode for a SD card. To change SD memory card bus width by ACMD6 (Set bus width) and
SDIO card bus width set Bus Width of Bus Interface Control register in CCCR.
5. If you want to change to 4-bit mode, set Data Transfer Width (WIDE4) to 1 in the Host Control register.
In another case (1-bit mode), set this bit to 0.
6. If SD memory card is used, go to 'End'. In case of other card, go to step (7).
7. Set "IENM" of the CCCR in a SDIO or SD combo card to 1 by CMD52.
8. Set Card Interrupt Status Enable to 1 in the Normal Interrupt Status Enable register.
START
SD Memory Only
Card ?
no
Change Bit Mode in Card
Change Bit Mode for Host
Figure 7-7
yes
(6 )
SD Memory Only
( 7)
Enable Card Interrupt in Card
( 8)
Enable Card Interrupt in Host
Change Bus Width Sequence
. Steps to change bit mode on SD Bus:
Figure 7-7
7 SD/MMC CONTROLLER
yes
Card ?
no
END
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