ETH: anybody used KSZ8863RLL?

[LCE]

Heyho,

until now I only used STM32 with the LAN8742, in a few weeks I'll get my 2nd custom board, but this time with the "dual" PHY KSZ8863RLL.

It's connected via RMII, for setup MDIO (and optionally I2C for the registers not accessible via MDIO).

Are there any known issues or "pitfalls" with this PHY?

Thanks in advance,
LCE

PS: interesting that there is no "ETH" label... :D

[Andrew Neil]

You mean this: https://www.microchip.com/en-us/product/lan8742 ?

and this: https://www.microchip.com/en-us/product/ksz8863 ?

As they're both Microchip products, have you asked Microchip for any guidance in moving from one to the other?

Do they have a migration guide?

Or on the Microchip Ethernet forum:

https://forum.microchip.com/s/sub-forums?&subForumId=a553l000000J2qRAAS&forumId=a553l000000J2q6AAC&subForumName=Ethernet&forumName=TCP%20%2F%20IP&page=1&offset=0

 

 

[Andrew Neil]

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@LCE wrote:

PS: interesting that there is no "ETH" label... :D

---

I guess that would go under 'Interface and connectivity ICs':

https://community.st.com/t5/interface-and-connectivity-ics/bd-p/interface-connectivity-ics-forum 

But do ST have any such chips?

[LCE]

> But do ST have any such chips?

No PHYs from ST.

That's why I ask here, in hope some other STM32 user has used the KSZ8863.

The Microchip forum / Ethernet feels like mostly dead.

[Andrew Neil]

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@LCE wrote:

The Microchip forum / Ethernet feels like mostly dead.

---

You can always contact Microchip Support direct: https://microchip.my.site.com/s/

https://www.microchip.com/en-us/support/design-help/client-support-services#

 

 

[LCE]

They have a migration guide between the KSZ8863 and another dual PHY.

 

[Andrew Neil]

Just noticed:

 

[LCE]

Yes, I already found these, one thread was started by me...

And I'm not too bad at googling! ;)

 

[LCE]

I'd rather have some insights from another STM32 / PHY user.

[Andrew Neil]

The products are agnostic to what microcontroller is used - a SAM would see the same as an STM.

Microchip would be able to tell you about the differences between their products.

[LCE]

> a SAM would see the same as an STM

Yes, but... the STM has surely another register setup.

Edit:

@Andrew Neil so until now we spammed this thread with "ask Microchip yes / no", please let's keep it at that.

And I hope some STM32 + KSZ8863 user finds the way here and shares some experience.

[Pavel A.]

We've made few projects with similar Microchip switches (not exactly this). The SPI or I2C interface gives easy access to all registers, make sure to connect it. The MDIO interface is provided for compatibility and is limited.

Note also their offering on the website: "Microchip's complimentary and confidential MicroCHECK design review service, which offers insight from the initial concept to the final PCB layout, is available to customers who are using our products in their projects. You can confidently submit your design materials in a secure and private setting, and our expert engineers will provide individualized feedback to enhance your design. "

Difference from the simple LAN... PHY is basically that the MCU is permanently connected to port #3, always at 100 Mbit/s, full duplex. So you can throw away code for detection of cable connect/disconnect, speed and duplex. Also throw away the whole MDIO config. stuff, you'll use the full management interface over I2C or SPI instead. Interrupt is optional; usually you can just poll the registers every so often.

[LCE]

@Pavel A. Thanks for the input!

For now I actually want to start with the MDIO (before struggling with another I2C peripheral), as it looks most stuff is handled automatically by the KSZ8863.

Checking for link status:

From another of your posts I already learned that the RMII side is always "linked" at 100-FULL.

But I think I could use the standard BSR register which each of the 2 PHYs has, with the same Link Status bit as LAN8742.

If that doesn't work, I'll try the "Auto-Negotiation Link Partner Ability Register" (reg 5), if the PHY doesn't show 100-FULL ability, link's not up.

 

The interrupt is also connected, but for now no intention to use it.

 

The Microchip offer is quite nice, but schematics and PCB layout are (usually) no problem.
Compared to the STM32-eval boards my PCBs could win prizes... :grinning_face_with_sweat: (okay, that's unfair when it comes to Nucleo with its 100 options per pin)

 

 

[LCE]

Here's some good info, saves me from trying to play with opcode 00 :D

https://community.st.com/t5/stm32-mcus-embedded-software/stm32h743-with-cube-1-40-ethernet-mdio-usage-for-phy/td-p/322108