DP83825EVM: update of User's Guide

please confirm,

Customer die below changes (sl. no. 1 &2 )  while connecting DP83825 EVM to customer board:

1) Remove: R9, R10, R17, R53, R54,  
2) Populate: R11, R12, R13, R14, R15, R16, R18

3) Solder clock to J12  (output to MAC)   - checked CLK_OUT signal at R30, it’s 50MHZ.

Is connection CLK_OUT signal to MAC needed?

ENET_RMII_CLK (25MHz) connection to R41 of DP83825 EVM to GPIO 73 of TMS320F28388D evm.

Regards, Holger

Hi Holger,

• May I ask where did you get all the information? Is the R9, R10, R17, R53, and R54 already populated out of the box from the DP83825 EVM?
• May I ask why did you populated R9,R10,R17,R53, and R54 beforehand? This is mainly used for external MAC loopback not for normal application.
• CLK_OUT should output 25MHz instead of 50MHz during normal operation. It will only enable 50MHz if you are using 825 as RMII slave where you are receiving 50MHz from the MAC side. CLK_OUT signal is not required connect to MAC

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Regards,

Hillman Lin

Hi Lin,
I got the info from the following e2e thread:

https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1225021/dp83825evm-updated-user-guide-to-match-latest-evm?tisearch=e2e-sitesearch&keymatch=%2522R9%252C%2520R10%252C%2520R17%252C%2520R53%2522#

I thought a loopback may be a good first test.

Customer still can't write to BMCR register. Could the CLK be the problem?

Regards, Holger

Hi Holger,

I think MDIO/MDC would be the issue if you are not able to write a register. Did you have a 2.2kohms pull up resistor on the MDIO line? Could you also probe the signal of MDIO and MDC lines?

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Regards,

Hillman Lin