Texas Instruments TMS320DM357 - Manual (Page 105)

4.37 Receive CPPI DMA State Word 0 (RCPPIDMASTATEW0)
4.38 Receive CPPI DMA State Word 1 (RCPPIDMASTATEW1)
www.ti.com Registers
Table 52. Transmit CPPI Completion Pointer (TCPPICOMPPTR) Field Descriptions
Bit Field Value Description
31-2 DESC_ADDR 0-3FFF FFFFh Descriptor Address
This field contains the 30-bit word aligned pointer of the end of packet descriptor that the
DMA has last processed
1 Reserved 0 Reserved
0 WRBK_MODE Writeback/Compare Mode. This bit controls the action that is to be taken when this location
is written.
0 Compare Mode. Indicates that the value that is presented on bits 31:2 of the write data
should be compared against the value that is currently contained in bits 31:2 of this location.
If the two match, the interrupt bit corresponding to this Tx Queue should be deasserted.
1 Writeback Mode. Indicates that the value that is presented on bits 31:2 of the write data
should be written to this location and the interrupt for this Tx Queue should be asserted. This
bit is read as zero.
The Receive CPPI DMA State Word 0 (RCPPIDMASTATEW0) is shown in Figure 52 and described in
Table 53 .
Figure 52. Receive CPPI DMA State Word 0 (RCPPIDMASTATEW0)
31 16
Reserved
R-0
15 8 7 0
Reserved SOP_BUFFER_OFFSET
R/W-0 R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 53. Receive CPPI DMA State Word 0 (RCPPIDMASTATEW0) Field Descriptions
Bit Field Value Description
31-8 Reserved 0-7FFF FFh Reserved
7-0 SOP_BUFFER_OFFSET 0-FFh Start of Packet Buffer Offset
Controls how many bytes the Receive DMA will skip at the beginning of the start
of packet buffer before beginning to fill the buffer with receive data. This field is
programmed by the Host software when the channel is set up to facilitate
addition of various protocol encapsulation headers for retransmission of received
packets.
The Receive CPPI DMA State Word 1 (RCPPIDMASTATEW1) is shown in Figure 53 and described in
Table 54 .
SPRUGH3 – November 2008 Universal Serial Bus (USB) Controller 105
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