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Observer
Observer
7,360 Views
Registered: ‎08-07-2013

SRIO differences between 1-lane and 4-lanes

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Hello,

 

I am trying to debug a connectivity problem with another ASIC. We started out with 4-lane SRIO. The link and port initialized.

Then Virtex-7 FPGA is transmitting data out using Message (type 11 format). The ASIC reports that it is not receiving the data transmitted.  I am attaching picture files that shows the transmitted data captured from Chipscope for both 1-lane and 4-lanes.

 

In the 4-lane version, I see the Packet Delimiter 7C followed by Ack ID, Format Type, Dest. ID, Source ID, Message Len, Mail box, Letter and user data. However, in the 1-lane version I DONT see Packet Delimiter, Ack ID etc. I just see Dest. ID followed by 0s for many cycles.

 

Both the 1-lane and 4-lanes version are built using IP Catalog Vivado 2014.2 and identical option selections except for the number of lanes.

srio_one_lane_adv_tx_Mar30.PNG
srio_four_lane_adv_tx_Mar20.PNG
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Observer
Observer
13,589 Views
Registered: ‎08-07-2013

I was using log_clk as Chipscope clock for both 4-lanes and 1-lane. However, for 1-lane log_clk frequency drops to 62.5MHz while it is 250MHz for 4-lane. As a result the capture for 1-lane missed cycles. I also put in a webcase for this and Gary Pan from Xilinx who responded suggested to use pcs_clk instead of log_clk for 1-lane Chipscope.

 

When I tried with pcs_clk the data transmission looks good and as expected. This resolves the discrepancy between 1-lane and 4-lanes.

View solution in original post

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Observer
Observer
13,590 Views
Registered: ‎08-07-2013

I was using log_clk as Chipscope clock for both 4-lanes and 1-lane. However, for 1-lane log_clk frequency drops to 62.5MHz while it is 250MHz for 4-lane. As a result the capture for 1-lane missed cycles. I also put in a webcase for this and Gary Pan from Xilinx who responded suggested to use pcs_clk instead of log_clk for 1-lane Chipscope.

 

When I tried with pcs_clk the data transmission looks good and as expected. This resolves the discrepancy between 1-lane and 4-lanes.

View solution in original post

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