Datasheet

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1109

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

The command ALL_SEND_CID and the fields and values for the HSMCI_CMDR are described in Table 41-6 and

Table 41-7.

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 Table 41-7).

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 HSMCI Interrupt Enable Register

(HSMCI_IER) allows using an interrupt method.

Table 41-6. ALL_SEND_CID Command Description

CMD Index Type Argument Response Abbreviation Command Description

CMD2 bcr

(1)

[31:0] stuff bits R2 ALL_SEND_CID

Asks all cards to send

their CID numbers on the

CMD line

Table 41-7. Fields and Values for HSMCI_CMDR

Field Value

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)