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Visitor pascalg
Registered: ‎04-20-2018

PCIe endpoint s_axis_tx_tready goes low, cfg_to_turnoff

Kintex 7 325T ffg900-2   (idcode 43651093)

Vivado 2018.3

PCIe endpoint : x4, 5GT/s, ref clock 100MHz, axi clk : 125MHZ/128bits, max payload size 512

Simulation OK : read / write registers, interrupts

On board :

LSPCI values seems ok (number of BAR, size of BAR…)

A PCIe reads return always ffffffff : s_axis_tx_tready is always set to 0 on Pcie interface (after few reads commands, PCIe bus is blocked)

We can see with debugger after startup, a pulse on :

  • Cfg_msg_received
  • Cfg_to_turnoff
  • Cft_turnoff_ok => s_axis_tx_tready goes low

Is it normal ?

Is it the L0s state ?

When we send a read command on PCIe, everything seems OK (data from user code is placed on s_axis_tx_tdata and s_axis_tx_tvalid is activated, both stays to 1) but s_axis_tx_tready don’t change to 1 and return value is ffffffff.

I don’t know where search (vhdl, IP PCIe configuration, OS…) ?


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2 Replies
Xilinx Employee
Xilinx Employee
Registered: ‎08-02-2007

回复: PCIe endpoint s_axis_tx_tready goes low, cfg_to_turnoff

cfg_to_trunoff is asserted is telling us that the host send an MSG of Power managment 

EP need to response to that message it is expected  that the core will goes to lower power status and not response to any TLP request

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Visitor pascalg
Registered: ‎04-20-2018

回复: PCIe endpoint s_axis_tx_tready goes low, cfg_to_turnoff

What wake up the EP ? :

 * an access of the root ? (read access must automatically wake up the EP ?)

 * is the "cfg_pm_wake" must be asserted before put read data on tx_.... ?

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