If we want to use x1 PCIE interface, which interface we can use as default? Lane0(PEX0) or Lane2(PEX2)?

Following JetsonTX2_OEM_Product_DesignGuide.pdf , 20170912 version
Page 27, Figure 13, there is statement: “default: PCIe x1(only PEX2_TX/RX lane used)”
Page 29, Table 24, PCIe Interface #0 (x1 default configuration- x4 optional) , PEX0_TX+/- (Lane0) description: “Default configuration(x1) uses only Lane 0.”

If we want to use x1 PCIE interface, which interface we can use as default? Lane0(PEX0) or Lane2(PEX2)?

Hi, sandra,

For default x1, PEX2 is the right choice.

The words about PCIe#0 have precondition, you can check the notes of table 15 as below:
4. Any x4 configuration can be used as a single x2 using only lanes 0 & 1 or a single x1 using only lane 0. Any x2 configuration
can be used as a single x1 using only lane 0.

For (JetsonTX2_OEM_Product_DesignGuide.pdf , 20170912 version)Table 15 on page 21, we’d like to use two USB3.0 port + one x1 PCIe , so we choose configs 4,
(1)to use USB_SS0 and USB_SS1 as two USB3.0 ports (but not use PEX_RFU due to we don’t need it),
(2)and use PEX0 as one x1 PCIE (but not use PEX2 due to we don’t need it)
Is it ok?

That’s ok.

SORRY,you make me confused
the table 15 show tahe the default config of CB is Congig #2, an it means there is a PCIe x4, so the PEX2 is the PCIe#0 lane 2.
but ,Page 29, Table 24, PCIe Interface #0 (x1 default configuration- x4 optional) , PEX0_TX+/- (Lane0) description: “Default configuration(x1) uses only Lane 0.”

4. Any x4 configuration can be used as a single x2 using only lanes 0 & 1 or a single x1 using only lane 0. Any x2 configuration can be used as a single x1 using only lane 0.

For config 2, x4 is default and only lane0 used for x1 configuration. But if x1 is default, then need to use PEX2 for that.

for the P2597_B04 carrier board,there is a PCIe x4 (config 2 shown in table 15 ) ,but the PCIe x4 is set as a x1 and uses only lane 0, using PEX0_TX/RX pins. is it right ?
In our design, we want to route a PCIe x1 to a FPGA, and we don’t want to change the default software configuration.
so,we should use the PEX0_TX/RX pins?