7 mci block register – Rainbow Electronics AT91CAP9S250A User Manual
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6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
41.10.7
MCI Block Register
Name: MCI_BLKR
Access Type: Read/write
• BCNT: MMC/SDIO Block Count - SDIO Byte Count
This field determines the number of data byte(s) or block(s) to transfer.
The transfer data type and the authorized values for BCNT field are determined by the TRTYP field in the MCI Command
Register (MCI_CMDR):
Warning: In SDIO Byte and Block modes, writing to the 7 last bits of BCNT field, is forbidden and may lead to unpredict-
able results.
• BLKLEN: Data Block Length
This field determines the size of the data block.
This field is also accessible in the MCI Mode Register (MCI_MR).
Bits 16 and 17 must be set to 0 if PDCFBYTE is disabled.
Note:
In SDIO Byte mode, BLKLEN field is not used.
31
30
29
28
27
26
25
24
BLKLEN
23
22
21
20
19
18
17
16
BLKLEN
15
14
13
12
11
10
9
8
BCNT
7
6
5
4
3
2
1
0
BCNT
TRTYP
Type of Transfer
BCNT Authorized Values
0
0
1
MMC/SDCard Multiple Block
From 1 to 65536: Value 0 corresponds to an infinite block transfer.
1
0
0
SDIO Byte
From 1 to 512 bytes: value 0 corresponds to a 512-byte transfer.
Values from 0x200 to 0xFFFF are forbidden.
1
0
1
SDIO Block
From 1 to 511 blocks: value 0 corresponds to an infinite block transfer.
Values from 0x200 to 0xFFFF are forbidden.
Other values
-
Reserved.