Data Transfer
4-14
ADSP-214xx SHARC Processor Hardware Reference
buffers consist of a 2 deep buffer and a shift register. The registers read
from or write to internal memory under DMA or processor core control.
Transmit Buffer
In the transmit path, the buffer is used to accept core data or DMA data
from internal memory. Data is transferred to the shift register to send
unpacked bytes to the ports. The least significant byte is transmitted first.
As each word is unpacked and transmitted, the next location in the FIFO
becomes available and a new DMA request is made if DMA is enabled. If
the shift register becomes empty, the
LCLKx
signal is deasserted.
Receive Buffer
In the receive buffer, data is transferred to the core or DMA from the buf-
fer whereas the shift register performs the packing, least significant byte
first (the least significant byte is placed in bits 7–0). The
LACKx
signal is
deasserted by the receiver as soon as it receives the first byte from trans-
mitter if the buffer already has a word (the receive buffer
RXLBx
is already
half full). The packing is done as shown in
.
For the ADSP-2146x processor, the least significant byte is trans-
mitted first. This is different to legacy processors (ADSP-2116x)
where the most significant byte is transmitted first.
Figure 4-9. Transmit and Receive Buffers
8
-BIT
BYTE
3
8
-BIT
BYTE 2
8
-BIT
BYTE 1
8
-BIT
BYTE 0
BIT
3
1
BIT
0
TRAN
S
MIT
RECEIVE
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Содержание SHARC ADSP-214 Series
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Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...