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MMC/SD/SDIO Register Manual
Table 24-67. MMCHS_SYSCTL
Address Offset
0x12C
Physical Address
0x4809 C12C
Instance
MMCHS1
0x480A D12C
MMCHS3
0x480B 412C
MMCHS2
Description
SD system control register. This register defines the system controls to set software resets, clock frequency
management and data timeout.
[31:24] = Software resets
[23:16] = Timeout control
[15:0] = Clock control
Type
RW
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Reserved
Reserved
DTO
CLKD
Reserved
ICS
ICE
SRA
SRD
SRC
CEN
Bits
Field Name
Description
Type
Reset
31:27
Reserved
Reserved bit field. Do not write any value.
R
0x00
26
SRD
Software reset for mmci_dat line. This bit is set to 1 for reset and released
RW
0
to 0 when completed .mmci_dat finite state machine in both clock domain
are also reset.
Here below are the registers cleared by the
[26] SRD bit:
MMCi.
MMCi.
: BRE, BWE, RTA, WTA, DLA and DATI
MMCi.
: SBGR and CR
MMCi.
: BRR, BWR, BGE and TC Interconnect and MMC
buffer data management is reinitialized.
0x0:
Reset completed
0x1:
Software reset for mmci_dat line
25
SRC
Software reset for mmci_cmd line. This bit is set to 1 for reset and released
RW
0
to 0 when completed. mmci_cmd finite state machine in both clock domain
are also reset.
Here below the registers cleared by the MMCi.
[25] SRC
bit:
MMCi.
: CMDI
MMCi.
: CC Interconnect and MMC command status
management is reinitialized.
0x0:
Reset completed
0x1:
Software reset for mmci_cmd line
24
SRA
Software reset for all. This bit is set to 1 for reset , and released to 0 when
RW
0
completed. This reset affects the entire host controller except for the card
detection circuit and capabilities registers.
0x0:
Reset completed
0x1:
Software reset for all the design
23:20
Reserved
Reserved bit field. Do not write any value.
R
0x0
19:16
DTO
Data timeout counter value and busy timeout. This value determines the
RW
0x0
interval by which mmci_dat lines timeouts are detected.
The host driver needs to set this bit field based on
- the maximum read access time (NAC) (See the SD Specification Part1
Physical Layer),
- the data read access time values (TAAC and NSAC) in the card specific
data register (CSD) of the card,
- the timeout clock base frequency (MMCi.
[5:0] TCF bits).
If the card does not respond within the specified number of cycles, a data
timeout error occurs (MMCi.
[20] DTO bit). The
MMCi.
[19,16] DTO bit field is also used to check busy
duration, to generate busy timeout for commands with busy response or for
busy programming during a write command. Timeout on CRC status is
generated if no CRC token is present after a block write.
0x0:
TCF x 2^13
3447
SWPU177N – December 2009 – Revised November 2010
MMC/SD/SDIO Card Interface
Copyright © 2009–2010, Texas Instruments Incorporated