i.MX6 ->Ethernet bandwith goes down to 0 Mbits/sec when I heat up the Atheros AR8035 a little bit

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i.MX6 ->Ethernet bandwith goes down to 0 Mbits/sec when I heat up the Atheros AR8035 a little bit

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marcelballmann
Contributor III

Hi,

I do a bandwith test with Iperf on the i.MX6, the phy is AR8035 connected with a RGMII Interface. I have done an eyediagram and this looks very good also when I heat up the board. But When I do the Iperf and heat up the board the Ethernet bandwith goes down to 0 Mbit/sec. I think it is the RGMII Interface. Did someone have an idea?

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igorpadykov
NXP Employee
NXP Employee

HI Marcel

one can check reference clock stability caused by crystal and

check timings shifting delay for clocks/data described in  IMX6DQCEC

sect.4.11.5.2 RMII Mode Timing.

Best regards

igor

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marcelballmann
Contributor III

Hi,

Thanks I will check this.

It is possible to tune this?

Best Regards

Marcel

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igorpadykov
NXP Employee
NXP Employee

i.MX6 can not tune delays, however

AR8035 may have registers for fine tuning.

Best regards

igor

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marcelballmann
Contributor III

I have another issue which will maybe helpfull. I have two equal systems one is a Quad ond is a Dual Lite. The Dual Lite has at room temp already 20 Mbit/sec  meanwhile the Quad has at room temp 380Mbit/sec. First I thought it is the AR8035 but now I'm thinking it will also be the i.MX6. I'm very confused?

Best Regards

Marcel

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igorpadykov
NXP Employee
NXP Employee

will Dual Lite will speed up with cooling with spray ?

If yes, then probably reason is the same, not optimized

delays and one can recheck them with

Table 63. RGMII Signal Switching Specifications1  IMX6SDLCEC .

Best regards

igor

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marcelballmann
Contributor III

Hi Igor,

we have seen that the CLK not 50/50(CLK low/high). It is 70/30 thats we sometimes the data is not sampled right. We have made a delay in the CLK. Now it is running also at hight Temp. We don't know why it is not 50/50, the Rev CLK is 125MHz and 50/50? Igor Thank you for your support.

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igorpadykov
NXP Employee
NXP Employee

duty cycle may be caused by weak drive strength,

one can try to increase it.

~igor

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