DS643 Datasheet, PDF (136/216 Pages) Xilinx, Inc – Soft Direct Memory Access (SDMA) support

LogiCORE IP Multi-Port Memory Controller (v6.06.a)
SDMA LocalLink Interface
The LocalLink Interface comprises:
• SDMA LocalLink Headers and Footers
• Transmit LocalLink Interface
• Receive LocalLink Interface
SDMA LocalLink Headers and Footers
SDMA uses LocalLink headers and footers to pass data in and out of the Buffer Descriptor User Application (APP#)
fields. This allows the software application to pass user-defined data to and from the user IP using the LocalLink
data stream.
For the transmit channel, the first descriptor describing a packet which includes APP0 to APP4, is transferred in the
header of the LocalLink data stream as shown in the following figure. For Transmit channel the Header is always
8 words long and the footer is always one word long. The footer data should be ignored. Figure 20 illustrates the
headers and footers.
X-Ref Target - Figure 20
NXDESC
_PTR
CURBUF CURBUF_ STS_CTRL
_ADDR LENGHT _APP0
APP1 APP2 APP3 APP4
PAYLOAD
I
Inserted into header
t
CURDESC_PTR
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
SOP =1
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
STS_CTRL_APP0
APP1
APP2
APP3
APP4
NXTDESC_PTR
CURBUF_ADDR
CURBUF_LENGTH
Figure 20: LocalLink Transmit Data Stream Header/Footer Assignment
EOP
DS643 February 22, 2013
www.xilinx.com
136
Product Specification