04-02-2020 07:30 AM
I'm interested in using of PS "Gigabit Ethernet MAC" (GEM) controller with option "External FIFO Interface" enabled.
I need to send some data from PL to ethernet interface. With "AR# 69490" and "UG1085" process of sendind data from PL to PS GEM is well documented.
My question is related to Rx packets. If I understand correctly, on packet receive, PS GEM controller outputs rx packet to "External FIFO Interface".
Would those Rx packets also be available on CPU side (LWIP)?
In my design I don't want to process Rx packets in PL but I would like to process them with CPU (through LWIP).
So PL should send data and CPU should process rx packets.
04-06-2020 06:13 AM - edited 04-06-2020 06:18 AM
There is no driver support for using an External FIFO interface.
So, You won't be able to process RX packets with PS through LWIP.
There is support for PS-GEM + 1000BASE-X PCS/PMA and PS-GEM + GMII2RGMII.
Could you provide more information about why do you want the mentioned solution?
04-06-2020 06:38 AM - edited 04-06-2020 06:40 AM
I'm generating/collecting some data in PL and PL then generates axi-stream from this data.
Then this axi-stream from PL will be converted to "GEM - TX FIFO packet stream".
RX packets that are coming into PS - GEM need to be processed in PS and not in PL.
Reason why i whant to use PS - GEM in EMIO configuration instead for example AXI-EthernetSubsystem
is that PS-GEM supports IEEE 1588 timestamping (Precission Time Protocol) which I need for my project.
To avoid using PS GEM external fifo interface and use only GMII and MDIO through EMIO, I can transfer this
data from PL into DDR, read it with CPU and then transfer it via LWIP to the PS-GEM. BUT I would like to avoid
this solution and perfom "direct" transfer from PL to PS-GEM.
04-06-2020 08:28 AM
1. IEEE 1588 support is available in the AXI Ethernet subsystem, and
2. You can still process the packets received in the PS with PS-DMA in PS-PL design instead of opting for external FIFO interface.
Could you try the same?
Please provide block diagram of your design for more questions. Thanks.
04-06-2020 01:11 PM