Preliminary
Registers
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9.4.19 Present State Register (SD_PSTATE)
The Host can get the status of the Host controller from this 32-bit read only register. The present state
register (SD_PSTATE) is shown in
and described in
.
Figure 9-47. Present State Register (SD_PSTATE)
31
25
24
23
20
19
18
17
16
Reserved
CLEV
DLEV
WP
CDPL
CSS
CINS
R-0
R-x
R-x
R-0
R-0
R-0
R-0
15
12
11
10
9
8
7
3
2
1
0
Reserved
BRE
BWE
RTA
WTA
Reserved
DLA
DATI
CMDI
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
LEGENDR/W = Read/Write; R = Read only; -n = value after reset
Table 9-29. Present State Register (SD_PSTATE) Field Descriptions
Bit
Field
Value
Description
31-25
Reserved
0
Reserved bit field. Do not write any value.
24
CLEV
SD_CMD line signal level. This status is used to check the SD_CMD line level to recover from
errors, and for debugging. The value of this register after reset depends on the SD_CMD line
level at that time.
Read 0
The SD_CMD line level is 0.
Read 1
The SD_CMD line level is 1.
23-20
DLEV
SD_DAT[3:0] line signal level
• SD_DAT3 => bit 23
• SD_DAT2 => bit 22
• SD_DAT1 => bit 21
• SD_DAT0 => bit 20
This status is used to check SD_DAT line level to recover from errors, and for debugging. This
is especially useful in detecting the busy signal level from SD_DAT0. The value of these
registers after reset depends on the SD_DAT lines level at that time.
19
WP
Write Protect. SD/SDIO1 only. SDIO cards only. This bit reflects the write protect input pin
(SDWP) level. The value of this register after reset depends one the protect input pin (SDWP)
level at that time.
Read 0
If SD_CON[8] WPP is cleared to 0 (default), the card is write protected, otherwise the card is
not write protected.
Read 1
If SD_CON[8] WPP is cleared to 0 (default), the card is not write protected, otherwise the card
is write protected.
18
Card Detect Pin Level. SD/SDIO1 only. SDIO cards only. This bit reflects the inverse value of
the card detect input pin (SDCD). Debouncing is not performed on this bit and is valid only
when Card State is stable. (SD_PSTATE[17] is set to 1). This bit must be debounced by
software. The value of this register after reset depends on the card detect input pin (SDCD)
level at that time.
Read 0
The value of the card detect input pin (SDCD) is 1.
Read 1
The value of the card detect input pin (SDCD) is 0.
17
Card State Stable. This bit is used for testing. It is set to 1 only when Card Detect Pin Level is
stable (SD_PSTATE[18] CPDL). Debouncing is performed on the card detect input pin
(SDCD) to detect card stability. This bit is not affected by software reset.
Read 0
Reset or Debouncing.
Read 1
Reset or Debouncing.
982
Secure Digital (SD)/—Secure Digital I/O (SDIO) Card Interface
SPRUGX9 – 15 April 2011
© 2011, Texas Instruments Incorporated
Содержание TMS320C6A816 Series
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