Preliminary
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Registers
9.4.20 Control Register (SD_HCTL)
This register defines the host controls to set power, wake-up and transfer parameters.
•
SD_HCTL[31:24] = Wake-up control
•
SD_HCTL[23:16] = Block gap control
•
SD_HCTL[15:8] = Power control
•
SD_HCTL[7:0] = Host control
NOTE:
If your device does not support MMC cards, then those bits in this register which are
meant for MMC card use should be assumed to be reserved.
The control register (SD_HCTL) is shown in
and described in
.
Figure 9-48. Control Register (SD_HCTL)
31
28
27
26
25
24
23
20
19
18
17
16
Reserved
OBWE
REM
INS
IWE
Reserved
IBG
RWC
CR
SBGR
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
15
12
11
9
8
7
6
5
4
3
2
1
0
Reserved
SDVS
SDBP
CDSS
CDTL
Rsvd
DMAS
HSPE
DTW
Rsvd
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R-0
R/W-2h
R/W-0
R/W-0
R-0
LEGENDR/W = Read/Write; R = Read only; -n = value after reset
Table 9-30. Control Register (SD_HCTL) Field Descriptions
Bit
Field
Value
Description
31-28
Reserved
0
Reserved bit field. Do not write any value.
27
OBWE
Wake-up event enable for 'out-of-band' Interrupt. This bit enables wake-up events for 'out-of-band'
assertion. Wake-up is generated if the wake-up feature is enabled (SD_SYSCONFIG[2]
ENAWAKEUP bit). The write to this register is ignored when SD_CON[14] OBIE bit is not set.
0
Disable wake-up on 'out-of-band' Interrupt
1
Enable wake-up on 'out-of-band' Interrupt
26
REM
Wake-up event enable on SD card removal. This bit enables wake-up events for card removal
assertion. Wake-up is generated if the wake-up feature is enabled (SD_SYSCONFIG[2]
ENAWAKEUP bit).
0
Disable wake-up on card removal
1
Enable wake-up on card removal
25
INS
Wake-up event enable on SD card insertion This bit enables wake-up events for card insertion
assertion. Wake-up is generated if the wake-up feature is enabled (SD_SYSCONFIG[2]
ENAWAKEUP bit).
0
Disable wake-up on card insertion
1
Enable wake-up on card insertion
24
IWE
Wake-up event enable on SD card interrupt. This bit enables wake-up events for card interrupt
assertion. Wake-up is generated if the wake-up feature is enabled (SD_SYSCONFIG[2]
ENAWAKEUP bit) and enable status bit is set (SD_IE[8] CIRQ_ENABLE bit).
0
Disable wake-up on card interrupt
1
Enable wake-up on card interrupt
23-20
Reserved
0
Reserved bit field. Do not write any value.
19
IBG
Interrupt block at gap. This bit is valid only in 4-bit mode of SDIO card to enable interrupt detection
in the interrupt cycle at block gap for a multiple block transfer. For SD card this bit should be
cleared to 0.
0
Disable interrupt detection at the block gap in 4-bit mode
1
Enable interrupt detection at the block gap in 4-bit mode
985
SPRUGX9 – 15 April 2011
Secure Digital (SD)/—Secure Digital I/O (SDIO) Card Interface
© 2011, Texas Instruments Incorporated