MPC5744P Ethernet port

[ebourque]

Hi, I have a question concerning the MPC5744P.

We are using the RMII port connected to an ethernet switch on the same board.

The question is regarding the RMII clock signal. The datasheet of the MPC5744P states that this is in output clock signal (clock is from from the MPC5744P to the ethernet switch).

This info seems to be colliding with the info from the ethernet switch manufacturer's datasheet which states that in RMII mode, the clock is fed from the switch to the MAC.

Can you help us with this matter?

Thank you!,

Emile

[PetrS]

Hi,

there will be some changes in next RM revision, refer to below pictures. From this there could be 2 options:

- 50MHz generated by PHY, then PG8 serves as RMII_CLK input and Aux Clock Sel10 must be configured to select this for ENET_CLK

- 50MHz generated internally and output on PG8. Aux Clock Sel10 configured for internal source (e.g PLL0), RCCR[RMII_CLK_EN] bit set (presently GCR register). PG8 connected to PHY clock input.

BR, Petr