14.5.4.2.3 RESP Line

The target device raises the RESP line at the end of a command if an error has occurred during processing. The target device can raise the RESP line only during CMDE or DATA commands. The host keeps the RESP line to 1 until the host acknowledges it. The procedure to acknowledge the error depends only on the type of command during which the target device has raised the RESP line.

• If the RESP line has been raised to 1 at the end of a CMDE command, then the host only needs to send a single CMDE or DATA command to acknowledge the error
• If the RESP line has been raised to 1 at the end of a DATA command, then the host must send two commands: a CMDE command first, then either a CMDE or a DATA command for the second command.

The input data carried by the DATA[15:0] lines during the commands sent to acknowledge the error are not relevant. However, CMDE or DATA commands are processed normally by the target device, as if the RESP line were 0.

On error acknowledge, the target device lowers the RESP line just after it has lowered the RDY line, hence at the beginning of the CMDE or DATA command processing.