RMII Configuration Support for QorIQ P1024RDB

[pavankumarg]

Hi,

I am currently using a P1024 processor. The hardware is configured for the RGMII on the evaluation board P1024RDB. There is an option for accessing RMII mode on the board but it seems to be connected via a CPLD through MUX selection. I was not able to configure the RMII in this mode. Can somebody help to configure the RMII interface on the reference board P1024RDB.

Thanks.

[alexander_yakov]

As far as I can guess, you are talking about PLD_TSEC1_TX_ER signal, which is generated by CPLD.

No, your understanding is incorrect, this signal is used as reset configuration signal at reset - cfg_rom_loc3

The buffer managed by CFG_DRV2_N signal - is enabled during POR configuration read.

Have a great day,
Alexander
TIC

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[pavankumarg]

I think I was not clear enough in my question, my question is that 

the control signals come from the CPLD for the selection pins in the QE MUX for the RMII mode selection. Could you

suggest how to select the RMII mode for the P1024RDB ?

Note - Image is taken from page 9 of the schematic of the P1024RDB.

[alexander_yakov]

SER5_ENET5 and TDMC_ENET5 are managed by CPLD depending on I2C_TSETDAT03 and I2C_TSETDAT02 inputs.

These inputs are connected to I2C expander chip PCA9555PW with reference designator U75.

According to my schematic, this chip is "DNP". I do not have the board under my hand.

Could you check if this I2C expander chip is soldered in your case?

[pavankumarg]

Yes, you are correct, the I2C expander is marked as DNP in my schematic, what should I check/do next in order to change to the RMII mode.

Thanks for the quick reply. 

[alexander_yakov]

Please check the board, if this expander is soldered or not soldered.

[pavankumarg]

No, I couldn't find the I2C expander, guess the portion for U75 might be soldered below, which I couldn't check because of the board housing and various other reasons. But I did check the UCC5 chip and the UCC1 chip both that can be configured for RMII and they both are not placed on the board. I guess without the RMII PHY chip there is no way that the RMII mode can be configured on the P1024RDB board. Do you know of any other workarounds to check the RMII configuration (probably with the on-board RGMII chip (AR8021) - though I checked the chip's datasheet and this doesn't seem to support RMII config. )

Thanks for your help.

Regards,

Pavankumar

[alexander_yakov]

Yes, I agree with you, AR8021 does not seem to support RMII mode.