AT91SAM9R64_14 Datasheet, PDF (640/903 Pages) ATMEL Corporation – Multi-layer AHB Bus Matrix for Large Bandwidth Transfers

38.9.7 MCI Block Register
Name:
MCI_BLKR
Access Type:
Read/write
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
• 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):
TRTYP
0
0
1
1
0
0
1
0
1
Other values
Type of Transfer
MMC/SDCard Multiple Block
SDIO Byte
SDIO Block
-
BCNT Authorized Values
From 1 to 65536: Value 0 corresponds to an infinite block transfer.
From 1 to 512 bytes: value 0 corresponds to a 512-byte transfer.
Values from 0x200 to 0xFFFF are forbidden.
From 1 to 511 blocks: value 0 corresponds to an infinite block transfer.
Values from 0x200 to 0xFFFF are forbidden.
Reserved.
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.
640 AT91SAM9R64/RL64
6289D–ATARM–3-Oct-11