Ethernet - SWR bit of DMA_MODE is set to 1 after Eth driver is initialized.

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User21537
Level 1
Level 1
Hi guys,
I am using TC397 step B for my Ethernet project with Eth driver provided by Infineon.
After the Eth driver is initialized, the bit SWR of DMA_MODE is set to 1 and never returns to 0.
as I read from datasheet, the SWR is software reset bit, it is normally set by software.
I do not know why the bit is set just after initialization. I think this is not the correct behavior.
Do you know how to fix it? Any causes can lead to this behaviors?

Thank you,
Dang Ho
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7 Replies
TBencher
Level 6
Level 6
25 solutions authored 25 likes received 5 questions asked
Hi DangHo,

maybe there are some synchronization issues. Please look at GETH_AI.H001 for MII and RMII and GETH_AI.H002 for RGMII from the Errata sheet (Rel. 1.4, 2020-10-23).

Regards,

Jens
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TBencher
Level 6
Level 6
25 solutions authored 25 likes received 5 questions asked
Hi DangHo,

try the GETH_TC.002 for RGMII and GETH_AI.H001 for MII and RMII from TC39x BD-Step Errata sheet.

The Errata sheet from the Post above is for TC36x AA Step.

Regards,

Jens
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MoD
Employee
Employee
50 likes received 500 replies posted 100 solutions authored
Please see description of the SWR bit:
This bit is automatically cleared after the reset operation is complete...
Setting 1 sets. Self-cleared. Setting 0 has no effect.
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User21537
Level 1
Level 1
Hi Jen,

Thank for your response. I just realized that my MCU is not provided with GREFCLK.

Is there any option that allow RGMII mode work without GREFCLK?

Thank you,
Dang
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MoD
Employee
Employee
50 likes received 500 replies posted 100 solutions authored
No, there is no option which allow RGMII mode without clock. Please see from description of SWR bit:
Note: The reset operation is complete only when all resets in all active clock domains are de-asserted.
Therefore, it is essential that all PHY inputs clocks (applicable for the selected PHY interface) are present for software reset completion.
The time to complete the software reset operation depends on the frequency of the slowest active clock.
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TBencher
Level 6
Level 6
25 solutions authored 25 likes received 5 questions asked
Hi DangHo,

please have a look at P11.5. There you have the GETH_GREFCLK (Gigabit Reference Clock input for RGMII (125 MHz high precission)).


Regards,

Jens
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User21537
Level 1
Level 1
JensM wrote:
Hi DangHo,

please have a look at P11.5. There you have the GETH_GREFCLK (Gigabit Reference Clock input for RGMII (125 MHz high precission)).


Regards,

Jens


Hi Jens,

After adding the clock on P11.5, my issue can be solved now. Thanks for your support.

I close this topic here..

Thanks all for your support,

Dang Ho
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