DP83848H not detected

Josh Worthington

Other Parts Discussed in Thread: TMS570LC4357, DP83848H

I am using a custom board with a TMS570LC4357 hooked up to a DP83848H. I am unable to read the Phy ID and the MDIO Alive register stays at 0. I am only using the DP83848H in RMII, so all unneeded pins have been left disconnected.

Here are the pins.

MDCLK - 2.34 MHz

PFBOUT/PFBIN1/PFBIN2 - 1.8 volts tied together

X1 - 50 MHz

RESET_N - 3.3 volts

RBIAS - 1.2 volts

I am unsure of what to check next to get this working, is there anything else I should measure?

over 10 years ago

0 Rob Rodrigues over 10 years ago

TI__Mastermind 19780 points

Hi Josh,

I am assuming MDIO access is working properly from the microcontroller.

Can you verify that RX_DV has a 2.2k pull-up resistor to put the DP83848H in RMII mode?

Would you also please verify that your PHY ID is correct on MDIO transactions? (Defaults to 0x1)

If you could share a schematic of the DP83848H portion of your board it would be helpful.

Best Regards,

0 Josh Worthington over 10 years ago in reply to Rob Rodrigues

Prodigy 230 points

There is a 2k pull up resistor on the RX_DV pin and the signal is high when the reset goes from low to high.

COL/PHYAD0 has been left disconnected and PHYAD1/PHYAD2 are low when reset goes from low to high, so we should be PHY ID 0x01.

I will have to ask if I can send part of the schematic and i'll let you know.

EDIT: Here is the schematic

SKM_C224e P15092312490.pdf

0 Josh Worthington over 10 years ago in reply to Josh Worthington

Prodigy 230 points

Looks like I found the issue. The original test project was setup using MII, but we changed it to RMII, but CCS wouldn't clean the project properly so the pinmux was always MII. I copied the project into a new one and that one cleaned properly and is working.

0 Rob Rodrigues over 10 years ago in reply to Josh Worthington

TI__Mastermind 19780 points

Glad to hear you got it fixed.

Regards,

Interface

Interface forum

DP83848H not detected