UM10503
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User manual
Rev. 1.3 — 6 July 2012
446 of 1269
NXP Semiconductors
UM10503
Chapter 20: LPC43xx SD/MMC interface
5. Software should look for Receive_FIFO_Data_request and/or data starvation by cpu
time-out conditions. In both cases, the software should read data from the FIFO and
make space in the FIFO for receiving more data.
6. When a Data_Transfer_Over interrupt is received, the software should read the
remaining data from the FIFO.
20.7.4.7 Single-Block or Multiple-Block Write
Steps involved in a single-block or multiple-block write are:
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 sends data in
blocks of size BLKSIZ each.
Table 332. CMD register settings for Single-block or Multiple-block Read
Name
Value
Comment
start_cmd 1
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
Can be 1 for commands to stop data
transfer, such as CMD12
Send_auto_stop
0/1
Set according to <tbd>
Transfer_mode
0
Block transfer
Read_write
0
Read from card
Cmd_index
Command index
Response_length
0
Can be 1 for R2 (long) response
Response_expect
1
Can be 0 for commands with no
response; for example, CMD0, CMD4,
CMD15, and so on
User-selectable
Wait_prvdata_complete
1
Before sending command on
command line, cpu should wait for
completion of any data command in
process, if any (recommended to
always set this bit, unless the current
command is to query status or stop
data transfer when transfer is in
progress)
Check_response_crc
1
0 – Do not check response CRC
1 – Check response CRC
Some of command responses do not
return valid CRC bits. Software should
disable CRC checks for those
commands in order to disable CRC
checking by controller.