DP83867IR: Using the COL / CRS Pins

Darren (FAE)

Part Number: DP83867IR

When connecting the DP83867IRPAP <-> MAC via RGMII interface, the COL/CRS (on the DP83867IR) pins aren't used.
Still, the DP83867IRPAP should be performing Collision / Carrier detection, right?

When performing collision/carrier detection, which signal is used to inform the MAC?

Regards,
Darren

over 3 years ago

0 David Creger over 3 years ago

TI__Mastermind 26932 points

Hi Darren,

The COL and CRS signals are not used in the RGMII interface, and can be left floating.

Thanks,

David

0 Darren (FAE) over 3 years ago in reply to David Creger

TI__Expert 5483 points

Hi David,

I understand COL and CRS are not used in RGMII and can be left floating.

As far as I know, the PHY still needs to perform "Carrier Sense" and "Collision Detection" though, right?
This is needed to see if a partner is trying to communicate on the bus or not.

But without COL or CRS, how does the PHY inform the MAC when a collison has occured, or that the bus is available?

0 David Creger over 3 years ago in reply to Darren (FAE)

TI__Mastermind 26932 points

Hi Darren,

Please see the following from the RGMII standard.

Thanks,

David

Interface

Interface forum

DP83867IR: Using the COL / CRS Pins