Altera Cyclone V Device Handbook page 720

11-42
cmd Register Settings for Single-Block and Multiple-Block Write
• Open-ended transfers For an open-ended block transfer, the byte count is 0. At the end of the data
transfer, software must send the STOP_TRANSMISSION command (CMD12).
• Fixed-length transfers The byte count is nonzero. You must already have written the number of
bytes to the bytcnt register. The controller issues the STOP command for you if you set the
send_auto_stop bit of the cmd register to 1. After completion of a transfer of a given number of
bytes, the controller sends the STOP command. Completion of the AUTO_STOP command is reflected
by the Auto Command Done interrupt. A response to the AUTO_STOP command is written to the
resp1 register. If software does not set the send_auto_stop bit in the cmd register to 1, software
must issue the STOP command just like in the open-ended case.
When the dto bit of the rintsts register is set, the data command is complete.
cmd Register Settings for Single-Block and Multiple-Block Write
Table 11-19: cmd Register Settings for Single-Block and Multiple-Block Write (Default)
Parameter
start_cmd
use_hold_reg
update_clk_regs_only
data_expected
card_number
transfer_mode
send_initialization
stop_abort_cmd
send_auto_stop
read_write
response_length
response_expect
Table 11-20: cmd Register Settings for Single-Block and Multiple-Block Write (User Selectable)
Parameter
wait_prvdata_complete
Altera Corporation
Value
1 This bit resets itself to 0 after the command is committed
(accepted by the BIU).
1 or 0 Choose the value based on speed mode being used.
0 Does not need to update clock parameters
1 Data command
1 For one card
0 Block transfer
0 Can be 1, but only for card reset commands such as SD/
SDIO GO_IDLE_STATE
0 Can be 1 for commands to stop data transfer such as SD/
SDIO STOP_TRANSMISSION
0 or 1 Refer to Auto Stop for information about how to set this
parameter.
1 Write to card
0 Can be 1 for R2 (long) responses
1 Can be 0 for commands with no response. For example,
SD/SDIO GO_IDLE_STATE, SET_DSR, GO_INACTIVE_
STATE etc.
Value
1 0 Sends command to the CIU immediately
1 Sends command after previous data transfer ends
†
†
†
†
Comment
†
Comment
SD/MMC Controller
Send Feedback
cv_54011
2013.12.30