Functional Description
21-26
ADSP-BF50x Blackfin Processor Hardware Reference
RSI Data Transmit Path
The transmit path consists of the WAIT_S, SEND, and BUSY states.
Before enabling the data path state machine via
RSI_DATA_CONTROL
, both
RSI_DATA_LGTH
and
RSI_DATA_TIMER
must be configured. Upon leaving
the IDLE state and entering the WAIT_S state, the RSI sets the
TX_ACTIVE
flag and copies
RSI_DATA_LGTH
into
RSI_DATA_CNT
. The behavior of the
SEND state is influenced by the transfer mode.
If the RSI is configured for stream-transfer mode, the RSI sends data to
the card until
RSI_DATA_CNT
expires, at which time the
DATA_END
flag is set
and the state machine returns to the IDLE state. Additionally, the transi-
tion of
RSI_DATA_CNT
to zero will result in the command path state
machine being activated if currently in the PEND state. If at any point
during the stream transfer the transmit FIFO becomes empty and data is
not available in the FIFO by the time the next transfer is due to take place,
the
TX_UNDERRUN
flag is set before returning to the IDLE state.
In block transfer mode,
DATA_BLK_LGTH
bytes are transmitted as specified
during the write to
RSI_DATA_CONTROL
, each byte transferred also results in
the decrementing of
RSI_DATA_CNT
. Upon completion of the block trans-
fer, the RSI appends an internally generated 16-bit CRC code and an end
bit before waiting for the card response on the
RSI_DATA0
line to indicate
whether the data was received correctly by the card. If the CRC response
token sent by the card indicates that the data was received correctly, the
DAT_BLK_END
flag is set before moving onto the BUSY state; otherwise, the
DAT_CRC_FAIL
flag is set before returning to the IDLE state. The decre-
menting of
RSI_DATA_CNT
to zero results in the
DAT_END
flag being set. If
RX_ OVERRUN
Receive FIFO over run error
RECEIVE
RX_FIFO_RDY
Valid data is available in the
receive FIFO
RECEIVE
Table 21-8. RSI_STATUS Flags (Cont’d)
RSI_STATUS Flag
Description
States Flag Set in
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...