UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
449 of 1269
NXP Semiconductors
UM10503
Chapter 20: LPC43xx SD/MMC interface
•
Send STOP command - Can be sent on the command line while a data transfer is in
progress; this command can be sent at any time during a data transfer. For
information on sending this command, refer to "No-Data Command With or Without
Response Sequence".
You can also use an additional setting for this command in order to set the Command
register bits (5-0) to CMD12 and set bit 14 (stop_abort_cmd) to 1. If stop
stop_abort_cmd is not set to 1, the user stopped a data transfer. Reset bit 13 of the
Command register (wait_prvdata_complete) to 0 in order to make the Module send
the command at once, even though there is a data transfer in progress.
–
Send ABORT command - Can be used with only an SDIO_IOONLY or
SDIO_COMBO card. To abort the function that is transferring data, program the
function number in ASx bits (CCCR register of card, address 0x06, bits (0-2) using
CMD52.
This is a non-data command. For information on sending this command, refer to
"No-Data Command With or Without Response Sequence".
Program the CMDARG register @0x28 with the appropriate command argument
parameters listed in
.
–
Program the Command register using the command index as CMD52. Similar to
the STOPcommand, set bit 14 of the Command register (stop_abort_cmd) to 1,
which must be done in order to inform the Module that the user aborted the data
transfer. Reset bit 13 (wait_prvdata_complete) of the Command register to 0 in
order to make the Module send the command at once, even though a data transfer
is in progress.
–
Wait for command_transfer_over.
–
Check response (R5) for errors.
•
During an open-ended card write operation, if the card clock is stopped because the
FIFO is empty, the software must first fill the data into the FIFO and start the card
clock before issuing a stop/abort command to the card.
20.7.5 Suspend or Resume Sequence
In an SDIO card, the data transfer between an I/O function and the Module can be
temporarily halted using the SUSPEND command; this may be required in order to
perform a high-priority data transfer with another function. When desired, the data transfer
can be resumed using the RESUME command.
Table 334. Parameters for CMDARG register
Bits
Contents
Value
31
R/W flag
1
30-28
Function number
0, for CCCR access
27
RAW flag
1, if needed to read after write
26
Don’t care
-
25-9
Register address
0x06
8
Don’t care
-
7-0
Write data
Function number to be aborted