Texas Instruments TMS320DM644x User Manual
www.ti.com
4.1
MMC Control Register (MMCCTL)
Registers
The MMC control register (MMCCTL) is used to enable or configure various modes of the MMC controller.
Set or clear the DATRST and CMDRST bits at the same time to reset or enable the MMC controller.
Set or clear the DATRST and CMDRST bits at the same time to reset or enable the MMC controller.
The MMC control register (MMCCTL) is shown in
and described in
Figure 18. MMC Control Register (MMCCTL)
31
16
Reserved
R-0
15
11
10
9
8
Reserved
PERMDX
PERMDR
Reserved
R-0
R/W-0
R/W-0
R-0
7
6
5
3
2
1
0
DATEG
Reserved
WIDTH
CMDRST
DATRST
R/W-0
R-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 6. MMC Control Register (MMCCTL) Field Descriptions
Bit
Field
Value
Description
31-11
Reserved
0
Reserved
10
PERMDX
Endian select when writing.
0
Little endian is selected.
1
Big endian is selected.
9
PERMDR
Endian select when reading.
0
Little endian is selected.
1
Big endian is selected.
8
Reserved
0
Reserved
7-6
DATEG
0-3h
DAT3 edge detection select.
0
DAT3 edge detection is disabled.
1h
DAT3 rising-edge detection is enabled.
2h
DAT3 falling-edge detection is enabled.
3h
DAT3 rising-edge and falling-edge detections are enabled.
5-3
Reserved
0
Reserved
2
WIDTH
Data bus width (MMC mode only).
0
Data bus has 1 bit (only DAT0 is used).
1
Data bus has 4 bits (all DAT0-3 are used).
1
CMDRST
CMD logic reset.
0
CMD line portion is enabled.
1
CMD line portion is disabled and in reset state.
0
DATRST
DAT logic reset.
0
DAT line portion is enabled.
1
DAT line portion is disabled and in reset state.
SPRUE30B – September 2006
Multimedia Card (MMC)/Secure Digital (SD) Card Controller
41