SAM3A4C Atmel Corporation, SAM3A4C Datasheet - Page 927

• Manufacturer Part Number: SAM3A4C
• Manufacturer: Atmel Corporation

37.8.1
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
Command - Response Operation
After reset, the HSMCI is disabled and becomes valid after setting the MCIEN bit in the
HSMCI_CR Control Register.
The PWSEN bit saves power by dividing the HSMCI clock by 2
inactive.
The two bits, RDPROOF and WRPROOF in the HSMCI Mode Register (HSMCI_MR) allow
stopping the HSMCI Clock during read or write access if the internal FIFO is full. This will guar-
antee data integrity, not bandwidth.
All the timings for High Speed MultiMedia Card are defined in the High Speed MultiMediaCard
System Specification.
The two bus modes (open drain and push/pull) needed to process all the operations are defined
in the HSMCI command register. The HSMCI_CMDR allows a command to be carried out.
For example, to perform an ALL_SEND_CID command:
The command ALL_SEND_CID and the fields and values for the HSMCI_CMDR Control Regis-
ter are described in
Table 37-6.
Note:
Table 37-7.
The HSMCI_ARGR contains the argument field of the command.
To send a command, the user must perform the following steps:
CMD
CMD Index
CMD2
Field
CMDNB (command number)
RSPTYP (response type)
SPCMD (special command)
OPCMD (open drain command)
MAXLAT (max latency for command to response)
TRCMD (transfer command)
TRDIR (transfer direction)
TRTYP (transfer type)
IOSPCMD (SDIO special command)
bcr means broadcast command with response.
S
T
ALL_SEND_CID Command Description
Fields and Values for HSMCI_CMDR Command Register
Type
bcr
Host Command
Content
Table 37-6
Argument
[31:0] stuff bits
CRC
and
Table
E
Z
37-7.
N
R2
Resp
ID
******
Cycles
Value
2 (CMD2)
2 (R2: 136 bits response)
0 (not a special command)
1
0 (No transfer)
X (available only in transfer command)
X (available only in transfer command)
0 (NID cycles ==> 5 cycles)
0 (not a special command)
Abbreviation
ALL_SEND_CID
Z
S
T
Content
PWSDIV
CID
Command
Description
Asks all cards to send
their CID numbers on
the CMD line
+ 1 when the bus is
SAM3X/A
SAM3X/A
Z
Z
Z
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