UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
455 of 1269
NXP Semiconductors
UM10503
Chapter 20: LPC43xx SD/MMC interface
•
Program the block size (BLKSIZ) register as shown below.
•
Program the Byte Count (BYTCNT) register as shown below.
20.7.5.2.4
Sending Command Completion Signal Disable
While waiting for the Command Completion Signal (CCS) for an outstanding RW_BLK,
the cpu can send a Command Completion Signal Disable (CCSD).
•
Send CCSD - Module sends CCSD to the CE-ATA device if the send_ccsd bit is set in
the CTRL register; this bit is set only after a response is received for the RW_BLK.
•
Send internal Stop command - Send internally generated STOP (CMD12) command
after sending the CCSD pattern. If send_auto_stop_ccsd bit is also set when the
controller is programmed to send the CCSD pattern, the Module sends the internally
generated STOP command on the CMD line. After sending the STOP command, the
Module sets the Auto Command Done bit in the RINTSTS register.
20.7.5.2.5
Recovery after Command Completion Signal Time-out
If time-out happened while waiting for Command Completion Signal (CCS), the cpu needs
to send Command Completion Signal Disable (CCSD) followed by a STOP command to
abort the pending ATA command. The cpu can program the Module to send internally
generated STOP command after sending the CCSD pattern
•
Send CCSD - Set the send_ccsd bit in the CTRL register.
•
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 internal STOP command - Set send_auto_stop_ccsd bit in the CTRL register,
which programs the cpu controller to send the internally generated STOP command.
After sending the STOP command, the Module sets the Auto Command Done bit in
the RINTSTS register.
20.7.5.2.6
Reduced ATA Command Set
It is necessary for the CE-ATA device to support the reduced ATA command subset. The
following details discuss this reduced command set.
Table 342. BLKSIZ register
Bits
Value
Comment
31:16
0
Reserved bits as zeroes (0)
15:0
512, 1024, 4096
MMC block size can be 512, 1024, or 4096
bytes as negotiated by CPU
Table 343. BYTCNT register
Bits
Value
Comment
31:0
N
block_size
byte_count should be integral multiple of
block size; for ATA media access commands,
byte count should be multiple of 4KB. (N
block_size = X
4KB, where N and X are
integers)