UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
454 of 1269
NXP Semiconductors
UM10503
Chapter 20: LPC43xx SD/MMC interface
1. Write the data size in bytes in the BYTCNT register @0x20.
2. Write the block size in bytes in the BLKSIZ register @0x1C. The Module expects a
single/multiple block transfer.
3. Program the CMDARG register @0x28 to indicate the Data Unit Count.
You should program the CMDARG, CMD, BLKSIZ, and BYTCNT registers according
to the following tables.
–
Program the Command Argument (CMDARG) register as shown below.
•
Program the Command (CMD) register as shown below.
Table 340. Parameters for CMDARG register
Bits
Contents
Value
31
R/W flag
1 (write) or 0 (read)
30-24
Reserved
0
23:16
Reserved
0
15:8
Data Count Unit
[15:8]
Data count
1:0
Data Count Unit
[7:0]
Data count
Table 341. CMD register settings
Name
Value
Comment
start_cmd 1
-
Css_expect
1
Command Completion Signal is expected;
set for RW_BLK if interrupts are enabled in
CE-ATA device, nIEN = 0
Read_ceata_device
0/1
1 – If RW_BLK or RW_REG read
update_clock_ registers_only
0
No clock parameters update command
card_number
0
Card number in use. Only zero is possible
because one card is support.
Data_expected 1
Send_initialization
0
Can be 1, but only for card reset commands,
such as CMD0
stop_abort_cmd 0
Send_auto_stop
0
Transfer_mode
0
Block transfer
Read_write
0/1
0 read from card,
1 - Write to card
Cmd_index
Command index
Response_length
0
Response_expect
1
User-selectable
Wait_prvdata_complete
1
0 – Sends command immediately
1 – Sends command after previous data
transfer over
Check_response_crc
1
0 – Do not check response CRC
1 – Check response CRC