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Registers
1297
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multimedia Card (MMC)/Secure Digital (SD) Card Controller
26.4.1 MMC Control Register (MMCCTL)
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.
The MMC control register (MMCCTL) is shown in
and described in
Figure 26-17. MMC Control Register (MMCCTL)
31
16
Reserved
R-0
15
11
10
9
8
Reserved
PERMDX
PERMDR
WIDTH1
R-0
R/W-0
R/W-0
R-0
7
6
5
3
2
1
0
DATEG
Reserved
WIDTH0
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 26-6. 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
WIDTH1
0-3h
Data bus width 1 (MMC mode only). Used in conjunction with the WIDTH0 bit.
0
Data bus has 1 bit (only MMCSD_DAT0 is used).
1h
Data bus has 4 bits (only MMCSD_DAT0-3 are used).
2h
Data bus has 8 bits (MMCSD_DAT0-7 are used).
3h
Reserved
7-6
DATEG
0-3h
MMCSD_DAT3 edge detection select.
0
MMCSD_DAT3 edge detection is disabled.
1h
MMCSD_DAT3 rising-edge detection is enabled.
2h
MMCSD_DAT3 falling-edge detection is enabled.
3h
MMCSD_DAT3 rising-edge and falling-edge detections are enabled.
5-3
Reserved
0
Reserved
2
WIDTH0
0-3h
Data bus width 0 (MMC mode only). Used in conjunction with the WIDTH1 bit.
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.