Change Bus Width Sequence - Samsung S3C2416 User Manual

S3C2416X RISC MICROPROCESSOR

4.6 CHANGE BUS WIDTH SEQUENCE

(1)
Disable Card Interrupt in Host
(3)
Mask Card Interrupt in Card
(4)
(5)
The sequence for changing bit mode on SD Bus is shown in Figure 20-7.
(1) Set Card Interrupt Status Enable(STACARDINT) 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 only 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.
(4) Change the bit mode for a SD card. Changing SD memory card bus width by ACMD6(Set bus width) and
changing SDIO card bus width by setting Bus Width of Bus Interface Control register in CCCR.
(5) In case of changing to 4-bit mode, set Data Transfer Width(WIDE4) in the Host Control register to 1. In
another case (1-bit mode), set this bit to 0.
(6) In case of SD memory only card, go to the '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 in the Normal Interrupt Status Enable register to 1.
START
(2)
SD Memory Only
Card ?
no
Change Bit Mode in Card
Change Bit Mode for Host
Figure 20-7. Change Bus Width Sequence
yes
(6)
SD Memory Only
(7)
Enable Card Interrupt in Card
(8)
Enable Card Interrupt in Host
HSMMC CONTROLLER
yes
Card ?
no
END
20-7