AM335x EtherCAT Link detection

Daisuke Maeda

Guru 20205 points

Other Parts Discussed in Thread: TLK110, TLK105, TLK106

Our customer is not using a default PHY, i.e. TLK105, TLK106 and TLK110.

The MII in PRU-ICSS has the pr1_mii0_rxlink and the pr1_mii1_rxlink for the LINK_MII signal. This signal used for link detection connects to typically an LED output signal of the PHY.
If the PHY does not have those signals, the LINK_MII signal is unavailable. If so, reading out MII management interface registers instead of using a dedicated link signal is needed.

Does the PRU with current version of Industrial SDK support the other operation for link detection instead of using a dedicated link signal?

Best regards,

Daisuke

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Daisuke,

You can try asking this also in the TI-RTOS forum, which also covers the Industrial SDK: http://e2e.ti.com/support/embedded/bios/default.aspx

0 PratheeshGangadhar over 11 years ago

TI__Mastermind 47531 points

Hi,

Can they try following modification in tiescbsp,c, bsp_init, before calling bsp_pruss_mdio_init

mdioParamsInit.enhancedlink_enable = TIESC_MDIO_RX_LINK_DISABLE; //This forces MDIO h/w state m/c based link detection

0 Daisuke Maeda over 11 years ago in reply to PratheeshGangadhar

Guru 20205 points

Hi PratheeshGangadhar and Biser,

Thank you for your reply.

Is the PRU ICSS covered in the TI-RTOS forum?

Best regards,

Daisuke

0 Daisuke Maeda over 11 years ago in reply to PratheeshGangadhar

Guru 20205 points

Hi PratheeshGangadhar,

The default PHY, i.e. TLK105, TLK106 and TLK110, supports the Fast Link Down mode.

When the PHY not to support the Fast Link Down mode is used, does the PRU support the Enhanced Link Detection? If the LINK_MII signal can be used, does the PRU support it?

Best regards,

Daisuke

0 Daisuke Maeda over 11 years ago in reply to PratheeshGangadhar

Guru 20205 points

Hi PratheeshGangadhar,

TLK105/TLK106/TLK110 supports the Fast Link Down mode, but other PHY does not support it.

http://download.beckhoff.com/download/Document/EtherCAT/Development_products/AN_PHY_Selection_GuideV2.2.pdf

When using the other PHY, does the PRU not support the Enhanced Link Detection?

Best regards,

Daisuke

0 SRIKANT IYER over 11 years ago in reply to Daisuke Maeda

TI__Prodigy 520 points

Daisuke,

The PRU firmware now supports Enhanced Link Detection. To use this feature from the PRU, you need to enable from EEPROM. Enable, in EEPROM word 0x0, bits 9, 12 and 13. Write the appropriate checksum in word 0x7. Restart and verify the settings in register 0x140. Enhanced link detection by PRU is then enabled on the board, irrespective of PHY settings.

0 PratheeshGangadhar over 11 years ago in reply to SRIKANT IYER

TI__Mastermind 47531 points

From h/w point of view pr1_mii0/1_rxer and pr1_mii0/1_rxlink must be connected to PHY. Here slow link detection of PHY is enhanced using RXER signal from PHY to improve the speed of link loss detection

For more details on PINMUX requirement of the firmware, see

http://processors.wiki.ti.com/index.php/AM335x_EtherCAT_firmware_API_guide#AM335x_SOC_pins_used_for_EtherCAT_functionality

0 Daisuke Maeda over 11 years ago in reply to SRIKANT IYER

Guru 20205 points

Hi SRIKANT,

Thank you for your reply.

I understand the PRU supports the Enhanced Link Detection without the Fast Link Down mode of PHY.

Best regards,

Daisuke

0 Daisuke Maeda over 11 years ago in reply to PratheeshGangadhar

Guru 20205 points

Hi PratheeshGangadhar,

Thank you for your reply.

Similarly, the ESC document describes that the link detection must not be used without LINK_MII signals.

http://download.beckhoff.com/download/Document/EtherCAT/Development_products/EtherCAT_ESC_Datasheet_Sec1_Technology_2i1.pdf
5.6.2 MI Link Detection and Configuration

"MI Link Detection and Configuration must not be used without link detection via LINK_MII signals,
because link loss reaction time would otherwise be to slow for redundancy operation. Enhanced Link
Detection might not be a suitable solution in this case if too few RX_ERR are issued to the ESC before
the PHY takes down the link.

NOTE: For testing it is possible to use MI Link Detection without LINK_MII signals: If the LINK_MII signals are
statically set to “no link”, only MI Link Detection is used."

Best regards,

Daisuke

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AM335x EtherCAT Link detection