Supported PHYs for PRUs

Matthias Fuchs

Other Parts Discussed in Thread: TLK110

Hi,

all AM335x ref boards are using the TLK110 MII PHY. Are there any alternative parts recommended? Are there any special

things to care about when selecting an alternative PRI attached MII PHY? We would like to use a micrel part like the KSZ8051 that we have already in use on other

boards. Because we are using the PRUs for EtherCAT and the PRU firmware comes a as unmodifiable object it must support our PHY out-of-the-box.

Did I miss any appnote on this?

Matthias

over 13 years ago

0 Frank Walzer over 13 years ago

TI__Mastermind 44306 points

Matthias,

we are aware there are other phys available. We are not locking customers into using TI phys only. Whenever we use proprietary features from TLK1xx we will make sure this is a customizable option through the ARM driver. One example is to enable fast link loss detection which is planned for one of the next EtherCAT firmware releases. Other features such as diagnostics may not be firmware dependent at all (just MDIO access).

Obviously we have no test beds for other phys at the moment. But I assume over time we will have experience based on customer designs.

There are no app notes planned for other phys. You may ask that other vendor to write up something to support AM335x based designs!

Regards.

0 -DK- over 13 years ago

TI__Mastermind 27890 points

To add a bit to Frank's excellent response, it is also important that when implementing any PHY that particular care is taken with the electrical interfaces. Best practices dictate that an interface timing analysis be performed on the relevant (MII, RMII, MDIO, etc) connections to ensure that they meet the timing requirements set forth by the PHY and the Link before committing the design to PCB.

0 Daisuke Maeda over 12 years ago in reply to -DK-

Guru 20205 points

Hi,

Are there the timing specifications for the PRU MII_RT (MII, MDIO) signals?

Best regards,

Daisuke

0 Daisuke Maeda over 12 years ago in reply to -DK-

Guru 20205 points

Hi,

Does the timing specification of the PRU MII_RT (MII, MDIO) signals meet the IEEE-802.3u (100Base-TX) specification?

Best regards,

Daisuke

0 Daisuke Maeda over 12 years ago in reply to -DK-

Guru 20205 points

Hi,

The MII and MDIO signal timing characteristics are specified in the following IEEE-802.3 specifications.

IEEE 802.3-2012 Section Two
http://standards.ieee.org/getieee802/download/802.3-2012_section2.pdf
22.3.1 Signals that are synchronous to TX_CLK [Page78]
22.3.2 Signals that are synchronous to RX_CLK [Page78]
22.3.4 MDIO timing relationship to MDC [Page79]

Do the MII and MDIO signal timing characteristics for the PRU MII_RT meet the IEEE-802.3 specification?

Best regards,

Daisuke

0 Daisuke Maeda over 12 years ago in reply to Daisuke Maeda

Guru 20205 points

Hi,

Here is my new post.

http://e2e.ti.com/support/arm/sitara_arm/f/791/t/289210.aspx

Best regards,

Daisuke

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Supported PHYs for PRUs