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Registered: ‎07-26-2013

PCIe PIPE simulation TXDATA not seen on GTXP GTXN pins

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Hello,

  I have generated the PCIe x1 gen1 PIPE interface using tranceiver wizard.

Virtex7 Device. The PIPE serdes was generated using Vivado 2013.2

I am using a Third party IP with PCIe MAC layer interfacing the xilinx PIPE interface GTs

 

The first byte of link training is not getting converted into serial data on serdes TX interface.

The first byte of TS1 sequence which K28.5 = 0xBC is available as TXDATA port of GT, but its equivalent 10bit code cant be seen on GTX pins.

 

The Background:

1) The 125 MHz PIPE Clock is generated by a PLL for tx/rx interface using 100MHz Refclk

2) The CPLL TXOUTCLK is 100MHz. I expected it to be 125MHz. Dont know why this freq gets generated

3) The CPLLREFCLKLOST is asserted right from the begining of simulation (Reasons unknown)

4) The MAC layer gives proper txdetectrx to GTs which is responded by GT with phystatus and rxstatus = 3'b011 as expected.

5) RXOUTCLK and RXSYNCDONE is always 0.

snapshot 1

 

So after the txelecidle is deasserted, the MAC layer starts sending data on txdata bus starting with 0xBC and txdatak[0] = 1'b1.

Also the GTX pair starts transaction after about 40ns after the txdata is presented to GTs. Is it expected to be this late? snapshot 2

 

 

Can anyone help understand whats could be the issue?

 

 

 

 

Thanks,

Sachin

 

pipe_1.png
pipe_2.png
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15,948 Views
Registered: ‎07-26-2013

Well Having connected the tx and rx serial ports in loopback mode showed some valid transactions happening.

So problem was not with GTs. The Mentor VIP had the issue causing simulations to stop.

Resolved it and PCIe x1 PIPE worked fine.

 

 

View solution in original post

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Highlighted
15,949 Views
Registered: ‎07-26-2013

Well Having connected the tx and rx serial ports in loopback mode showed some valid transactions happening.

So problem was not with GTs. The Mentor VIP had the issue causing simulations to stop.

Resolved it and PCIe x1 PIPE worked fine.

 

 

View solution in original post

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