DP83826E: Enhanced MODE: Does the link/activity pin LED blinking conform to EtherCAT's timing diagram?

Kevin Raman

Part Number: DP83826E

Hi,

I have several questions to ask if I was to use DP83826 as our PHY chip for the 3rd port of our AX58100 EtherCAT Slave Controller (ESC).

1. Can I avoid using an MCU to program the PHY chip if I run it on ENHANCED MODE?

2. If I run it on ENHANCED MODE (EtherCAT compliant), will the blinking speed of the activity/link pin conform to EtherCAT's timing diagram standards? What is the timing diagram of this pin?

- The datasheet did not mention what is the blinking speed of this pin in Enhanced mode.

3. Could there be any foreseeable issue that might occur with this combination of components?

I appreciate any help or guidance. Thank you and take care

9 months ago

0 Alvaro (Al-vuh-roe) Reyes 9 months ago

TI__Mastermind 19621 points

Hi Kevin,

Thank you for reaching out. I believe this document will have the answers you're looking for.

https://www.ti.com/lit/an/snla344c/snla344c.pdf?ts=1711043267540&ref_url=https%253A%252F%252Fwww.google.com%252F

Regards,

Alvaro

0 Kevin Raman 9 months ago in reply to Alvaro (Al-vuh-roe) Reyes

Prodigy 50 points

Hi Alvaro,

I've read the application note that you've sent, but there is still no conclusive or definitive statement on the LED blinking timing diagram.

0 Alvaro (Al-vuh-roe) Reyes 9 months ago in reply to Kevin Raman

TI__Mastermind 19621 points

Hi Kevin,

Are you referring to the actual frequency at which the LED will blink during activity? If so, what exactly are the EtherCAT specs for this?

Regards,

Alvaro

0 Kevin Raman 9 months ago in reply to Alvaro (Al-vuh-roe) Reyes

Prodigy 50 points

Hi Alvaro,

Yes, the frequency that the LED will blink during activity.

The EtherCAT specs is as shown below

0 Alvaro (Al-vuh-roe) Reyes 9 months ago in reply to Kevin Raman

TI__Mastermind 19621 points

Hi Kevin,

Thank you for sending the table. Please allow me another day to discuss with my team.

Regards,

Alvaro

0 Alvaro (Al-vuh-roe) Reyes 9 months ago in reply to Alvaro (Al-vuh-roe) Reyes

TI__Mastermind 19621 points

Hi Kevin,

Yes the DP83826 can meet this spec, this can be configured in Reg 0x18

Regards,

Alvaro

0 Kevin Raman 9 months ago in reply to Alvaro (Al-vuh-roe) Reyes

Prodigy 50 points

Hi Alvaro,

May I know which value is the default value if we were to use it in hardware Enhanced mode? We are trying to eliminate the use of an MCU as we have limited board space.

0 Kevin Raman 9 months ago in reply to Kevin Raman

Prodigy 50 points

Since we need 20Hz blinking rate, may I know how can I program the PHY chip through Serial Management Interface? I can't find any example or connections to the PHY chip for the purpose of programming it

0 Alvaro (Al-vuh-roe) Reyes 9 months ago in reply to Kevin Raman

TI__Mastermind 19621 points

Hi Kevin,

The default value is 2h, 5 Hz. To change this setting, register access is necessary. The SMI gives us access to registers, via the MDC & MDIO lines. These would be connected to some kind of controller (MCU, MPU, SoC, etc.) which can then program the PHY by writing to different registers.

Could you send me the document where you found this LED blink rate requirement? I checked the Beckhoff's Ethercat PHY Selection Guide and didn't see this requirement listed.

Regards,

Alvaro

0 Kevin Raman 9 months ago in reply to Alvaro (Al-vuh-roe) Reyes

Prodigy 50 points

Hi, Alvaro.

Thank you for the information.

You can access the document here: https://www.ethercat.org/memberarea/Download/ETG1300_V1i1i1_S_R_IndicatorLabelingSpecification.pdf

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DP83826E: Enhanced MODE: Does the link/activity pin LED blinking conform to EtherCAT's timing diagram?