Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

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SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

The command ALL_SEND_CID and the fields and values for the HSMCI_CMDR are described in 

 and 

Note:

1. bcr means broadcast command with response.

The HSMCI_ARGR contains the argument field of the command.
To send a command, the user must perform the following steps:



Fill the argument register (HSMCI_ARGR) with the command argument.



Set the command register (HSMCI_CMDR) (see 

The command is sent immediately after writing the command register.
While the card maintains a busy indication (at the end of a STOP_TRANSMISSION command CMD12, for 

example), a new command shall not be sent. The NOTBUSY flag in the Status Register (HSMCI_SR) is asserted 

when the card releases the busy indication.
If the command requires a response, it can be read in the HSMCI Response Register (HSMCI_RSPR). The 

response size can be from 48 bits up to 136 bits depending on the command. The HSMCI embeds an error 

detection to prevent any corrupted data during the transfer.
The following flowchart shows how to send a command to the card and read the response if needed. In this 

example, the status register bits are polled but setting the appropriate bits in the Interrupt Enable Register 

(HSMCI_IER) allows using an interrupt method.

CMD2

bcr

[31:0] stuff bits

R2

ALL_SEND_CID

Asks all cards to send 

their CID numbers on the 

CMD line

CMDNB (command number)

2 (CMD2) 

RSPTYP (response type)

2 (R2: 136 bits response)

SPCMD (special command)

0 (not a special command)

OPCMD (open drain command)

1

MAXLAT (max latency for command to response)

0 (NID cycles ==> 5 cycles) 

TRCMD (transfer command)

0 (No transfer)

TRDIR (transfer direction)

X (available only in transfer command)

TRTYP (transfer type)

X (available only in transfer command)

IOSPCMD (SDIO special command)

0 (not a special command)