DS643 Datasheet, PDF (137/216 Pages) Xilinx, Inc – Soft Direct Memory Access (SDMA) support

LogiCORE IP Multi-Port Memory Controller (v6.06.a)
For the Receive channel as shown in Figure 21:
• The header must be only one word long and the data is discarded by the SDMA.
• The footer must be exactly eight words long.
• The last descriptor is populated with the LocalLink footer user App Fields, App0 and App1 to App4.
X-Ref Target - Figure 21
Header
PAYLOAD
NXDESC
_PTR
CURBUF CURBUF_ STS_CTRL
_ADDR LENGTH _APP0
APP1 APP2
APP3 AP
Ignored for receive
Ignored for receive
CURDESC_PTR
The SOP bit in STS_CTRL_APP0
will be set indicating that the buffer
associated with this descriptor contains
the first byte of the packet.
BD 1
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
BD 2
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
BD 3
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
The EOP bit in STS_CTRL_APP0
will be set indicating that the buffer
associated with this descriptor contains
the last byte of the packet.
BD 4
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
BD 5
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
Figure 21: LocalLink Receive Data Stream Footer Assignment
DS643 February 22, 2013
www.xilinx.com
137
Product Specification