Network packet loss.

[1773750986]

I use the imx6q+KSZ8041FTLIphy chip, according to the official reference design of the RMII interface network,But there is a phenomenon of network packet loss.

Constantly power off and power off to test the packet loss phenomenon. I found that if there is a packet loss at a certain power-on, if it is not powered, it will continue to lose packets. This phenomenon may disappear if the power is turned off. However, there are several boards, the phenomenon is more serious, it may be tested several times, this phenomenon will occur, but some boards are difficult to test this problem.

in the schematic，Y3 is not  populated！

[igorpadykov]

Hi zhang

may be recommended not to turn off phy clock, as some issues were reported  on

net: ethernet: fsl: don't en/disable refclk on open/close - Patchwork 

also for packet loss one can check suggestions on

i.MX6 Gigabit Ethernet - Boundary Devices 

Best regards
igor
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[1773750986]

Hi,I have  solved this problem.The problem lies in the resistor R146. Although I did not use the external crystal Y3 which is not populated, but the resistor  R146 was soldered to the board. After I removed the resistor, and continuously powered down and up the board to test the net  300 times. No packet loss occurred.  I want to know why ?

pic below is the scope of RMII_REF_CLK with R146

PIC below is the scope  of RMII_REF_CLK without R146