AM6442: Two PHY's with one CLKOUT

Hello Josef,

No, CLKOUT is intended for a point-point clock topology.

Please note that CLKOUT functionality has not completed validation and characterization yet. If you are building boards today, I would recommend including the ability to source a crystal-based 50MHz clock to the interface as an option.

EDIT:

Just wanted to add some clarity to my original response. Routing a single clock to two different devices can result in signal integrity issues unless great care is taken to ensure that reflections are controlled. In your case, where you are wishing to provide the 25MHz functional clock to two different PHYs, I would recommend that you implement a dual-output clock buffer and locate it near the SoC source. This would allow for the routing of the SoC 25MHz CLKOUT to two different devices while still maintaining signal integrity.

My 50MHz comment was specific to RMII and the desire to provide the bus clock to both SoC and MAC (Internal Clock Mode). As I mentioned, we have not completed validation and characterization for this functionality yet so I would recommend that allowances for an externally-clocked mode of RMII operation be made.