Information

Address: SDHC_XFERTYP is 400B_1000h base + Ch offset = 400B_100Ch
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R
0
CMDINX CMDTYP
DPSEL
CICEN CCCEN
0
RSPTYP
W
Reset
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bit
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R
0
MSBSEL
DTDSEL
0
AC12EN
BCEN
DMAEN
W
Reset
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
SDHC_XFERTYP field descriptions
Field Description
31–30
Reserved
This read-only field is reserved and always has the value zero.
29–24
CMDINX
Command Index
These bits shall be set to the command number that is specified in bits 45-40 of the command-format in
the SD Memory Card Physical Layer Specification and SDIO Card Specification.
23–22
CMDTYP
Command Type
There are three types of special commands: suspend, resume and abort. These bits shall be set to 00b
for all other commands.
• Suspend command: If the suspend command succeeds, the SDHC shall assume that the card bus
has been released and that it is possible to issue the next command which uses the DAT line. Since
the SDHC does not monitor the content of command response, it does not know if the suspend
command succeeded or not. It is the host driver's responsibility to check the status of the suspend
command and send another command marked as suspend to inform the SDHC that a suspend
command was successfully issued. After the end bit of command is sent, the SDHC de-asserts read
wait for read transactions and stops checking busy for write transactions. In 4-bit mode, the interrupt
cycle starts. If the suspend command fails, the SDHC will maintain its current state, and the host
driver shall restart the transfer by setting the PROCTL[CREQ].
• Resume command: The host driver re-starts the data transfer by restoring the registers saved
before sending the suspend command and then sends the resume command. The SDHC will check
for a pending busy state before starting write transfers.
• Abort command: If this command is set when executing a read transfer, the SDHC will stop reads to
the buffer. If this command is set when executing a write transfer, the SDHC will stop driving the
DAT line. After issuing the abort command, the host driver should issue a software reset (abort
transaction).
00b Normal other commands
01b Suspend CMD52 for writing bus suspend in CCCR
10b Resume CMD52 for writing function select in CCCR
11b Abort CMD12, CMD52 for writing I/O abort in CCCR
21
DPSEL
Data Present Select
Table continues on the next page...
Memory map and register definition
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
1388 Freescale Semiconductor, Inc.