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Not applicable
Hi all,

As a bit on an aside, would anyone know the thinking, behind the following difference, with the XMC4800 Relax board? Does some convention, apply? I couldn't find anything concrete. We've followed suit, for our project board.

For the Ethernet port, the green LED is PHY pin driven, and the yellow LED is XMC pin driven, ie software control. But for the EtherCAT In and Out ports, the opposite is true. Details, below.

- With the Ethernet port, the green LED is driven by the Micrel KSZ8081RNA PHY LED0 output (default on for link, blink for activity, otherwise off).The PHY LED1 output (default 10/100 speed indication), is not-connected. The yellow LED is driven by XMC pin 2.10. The DAVE example project for Modbus TCP, doesn't drive the pin. For our project, I've added toggle after each packet send, LED off on comms timeout.

- With the EtherCAT In and Out port (lets call them EI and EO, respectively), the yellow LED is driven by the Broadcom BCM5241XA1KMLG PHY LED1 output, seemingly on for link activity, otherwise off. (The LED state goes also to XMC pins 6.3 for EI, 3.12 for EO, for EtherCAT Slave Code (ESC) monitoring use). The PHY LED2 output goes to 3V3 via 2K2. The green LED is driven by XMC pin 1.15 for EI, 3.4 for EO. The ESC blinks, for activity. The XMC4300 Relax board is the same, except latter pins 1.12 and 0.11.

Best regards,

David
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Not applicable
Hi all,

I've found 25% of the answer:

The green LED, for EI and EO, is software driven, for the following reason: There is a Beckhoff EtherCAT specification, that calls for green LED steady and flicker behaviour, that a PHY LED output pin can provide, but also optional flash patterns that it cannot. Specifically, single / double / triple and inverted-double patterns. And the ESC authors opted to implement the single and double patterns. Hence, the green LED had to be software driven. At least, that's the understanding I've arrived at.

The mentioned specification, is 'EtherCAT Indicator and Labeling Specification ETG.1300 S (R) V1.1.1'. It calls for a green LED to indicate link and activity status. And optionally, port-closed and auto-negotiation error status, courtesy the mentioned patterns.

The standard doesn't mention a yellow LED, though. I guess, the Infineon XMC4800 / XMC4300 Relax board designers opted to drive the yellow LED with a Broadcom BCM5241XA1KMLG PHY LED. And of the two such outputs available, they went for the LED1 nolink / nolink output, as opposed to the LED2 output, which I would guess indicates 10 / 100 MHz. Some guessing here, as the 2-page datasheet / product brief for that PHY, just says there are LED Drivers, but doesn't indicate their function.

As for the Ethernet port, there seems to be no standard, for the green LED and yellow LED. And quite a lot of market variety, between products, in how they are driven. Perhaps, the Relax board designers opted for flexibility, by having one LED driven by a Micrel KSZ8081RNA PHY output, and the other by software. And they opted to have the green LED driven by the LED0 nolink / link / activity output, as opposed to the LED1 10 / 100 MHz output. With the yellow LED driven by software. Perhaps following suit from the Ethernet implementation on other boards produced..

Best regards,

David
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Not applicable
Hi,

About the Relax board EI+EO Broadcom BCM5241XA1KMLG PHYs, I've now been given the full 77-page datasheet.

In the LED section, I can see it says LED1 and LED2 output pin function, is determined by the PHY-sensed state of those pins at power-up reset (POR).

The PHY will sense LED1 and LED2 pins high, courtesy external pull-ups, via R270 and yellow LED to 3V3, and via 2K2 to 3V3, respectively.

This selects steady link function for LED1, as goes also to mentioned XMC input pin for ESC monitoring use. And 10Hz blinking activity for LED2, unseen as just goes via 2K2 to 3V3.

Further, the section says if the sensed power-up state of LED1 is high, then the output subsequently is low for the selected function, and vice-versa, likewise for LED2. So for LED1, low for link, as needed by the ESC, and lighting the yellow LED, as observed.

Best regards,

David
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User9154
Level 4
Level 4
Hi David,
we have used KSZ8081 PHY on or new board too..
can you send me this full 77-page datasheet of BCM5241XA1KMLG PHYs
my email is brudny@befra.cz
thank you
zbyno
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