at91sam9260-cj ATMEL Corporation, at91sam9260-cj Datasheet - Page 557

• Manufacturer Part Number: at91sam9260-cj
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 35-9. Command/Response Functional Flow Diagram
Note:
35.7.2
6221G–ATARM–31-Jan-08
1. If the command is SEND_OP_COND, the CRC error flag is always present (refer to R3 response in the MultiMedia Card
Data Transfer Operation
specification).
Check error bits in the
The MultiMedia Card allows several read/write operations (single block, multiple blocks, stream,
etc.). These kind of transfers can be selected setting the Transfer Type (TRTYP) field in the MCI
Command Register (MCI_CMDR).
These operations can be done using the features of the Peripheral DMA Controller (PDC). If the
PDCMODE bit is set in MCI_MR, then all reads and writes use the PDC facilities.
In all cases, the block length (BLKLEN field) must be defined either in the mode register
MCI_MR, or in the Block Register MCI_BLKR. This field determines the size of the data block.
Enabling PDC Force Byte Transfer (PDCFBYTE bit in the MCI_MR) allows the PDC to manage
with internal byte transfers, so that transfer of blocks with a size different from modulo 4 can be
supported. When PDC Force Byte Transfer is disabled, the PDC type of transfers are in words,
otherwise the type of transfers are in bytes.
Wait for command
status register
ready status flag
(1)
Set the command argument
MCI_ARGR = Argument
Read response if required
MCI_CMDR = Command
Status error flags?
Set the command
Read MCI_SR
RETURN OK
CMDRDY
1
(1)
RETURN ERROR (1)
Yes
0
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