ADSP-BF50x Blackfin Processor Hardware Reference
21-21
Removable Storage Interface
completion of sending the command depends upon whether the com-
mand expects a response back from the card. If no response is expected,
the RSI clears the
CMD_ACT
flag and sets the
CMD_SENT
flag to indicate that a
command operation without a response has been completed and then the
state transitions to the IDLE state. If a response is expected, the RSI enters
the WAIT state.
WAIT State
Upon entering the WAIT state, the RSI awaits the response to be received
on the
RSI_CMD
signal. Upon entering this state, an internal timer starts
running. If the response is not received within 64
RSI_CLK
cycles
(max. NCR), the
CMD_TIMEOUT
flag is set and the
CMD_ACT
flag is cleared.
The state machine then enters the IDLE state, awaiting the next action.
If a response is detected as being sent back from the card as indicated by
the “0” start bit on the
RSI_CMD
signal, the RSI transitions to the
RECEIVE state to receive a 48- or 136-bit response.
The WAIT state is also capable of detecting card interrupts. This is an
optional feature that applies only to MMC cards. This feature is enabled
by setting the
CMD_INT_EN
bit within
RSI_COMMAND
. When
CMD_INT_EN
is
set, the timeout timer that is normally started upon entry to the WAIT
state is disabled. The RSI remains in this state until a card interrupt is
detected. Cards that implement this interrupt feature may have functions
that result in the response being delayed and triggered by some internal
event in the card. Once the event is triggered the card then sends the
response. The RSI then detects this start bit of the response then proceeds
to the RECEIVE state.
RECEIVE State
The RSI reads in the response from the card on the
RSI_CMD
signal when
in the RECEIVE state. Upon receiving either the short or long response,
the
CMD_ACT
flag is cleared and the
CMD_RESP_END
flag is set if the response
passed the CRC check. A CRC failure in the response results in the
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...