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MMC/SD/SDIO Register Manual
Bits
Field Name
Description
Type
Reset
0x2:
TCF x 2 delay (card clock period).
0xFFFE:
TCF x 65534 delay (card clock period).
0xFFFF:
TCF x 65535 delay (card clock period).
Table 24-46. Register Call Summary for Register MMCHS_PWCNT
MMC/SD/SDIO Register Manual
•
Table 24-47. MMCHS_BLK
Address Offset
0x104
Physical Address
0x4809 C104
Instance
MMCHS1
0x480A D104
MMCHS3
0x480B 4104
MMCHS2
Description
Transfer Length Configuration register
This register shall be used for any card.
Type
RW
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
NBLK
Reserved
BLEN
Bits
Field Name
Description
Type
Reset
31:16
NBLK
Blocks count for current transfer.
RW
0x0000
This register is enabled when Block count Enable
(MMCi.
[1] BCE bit) is set to 1 and is valid only for
multiple block transfers. Setting the block count to 0 results no
data blocks being transferred. Note: The host controller
decrements the block count after each block transfer and stops
when the count reaches zero. This register can be accessed only
if no transaction is executing (i.e., after a transaction has stopped).
Read operations during transfers may return an invalid value and
write operation will be ignored. In suspend context, the number of
blocks yet to be transferred can be determined by reading this
register. When restoring transfer context prior to issuing a Resume
command, The local host shall restore the previously saved block
count.
0x0:
Stop count
0x1:
1 block
0x2:
2 blocks
0xFFFF:
65535 blocks
15:11
Reserved
Reserved bit field. Do not write any value
R
0x00
10:0
BLEN
Transfer Block Size. This register specifies the block size for block
RW
0x000
data transfers. Read operations during transfers may return an
invalid value, and write operations are ignored. When a CMD12
command is issued to stop the transfer, a read of the BLEN field
after transfer completion (MMCi.
[1] TC bit set to 1)
will not return the true byte number of data length while the stop
occurs but the value written in this register before transfer is
launched.
0x0:
No data transfer
0x1:
1 byte block length
0x2:
2 bytes block length
0x3:
3 bytes block length
0x1FF:
511 bytes block length
0x200:
512 bytes block length
0x3FF:
1023 bytes block length
3435
SWPU177N – December 2009 – Revised November 2010
MMC/SD/SDIO Card Interface
Copyright © 2009–2010, Texas Instruments Incorporated