DP83848 and STM32F407VET6 no communication.

Vladimir Shein

I have the subjes mounted on my development board for academic project.

I use interface RMII. 50 Mhz clk goes from PA8 pin. (PLL_CLK=100MHz / 2). Xtal is 25 MHz 20 pf CL and 30 ppm. The clocking seems to be stable.

Schematic are typical for RMII and other parts too. RESET and POWER_DOWN pins are at 3.3V. I checked soldering and schematic but no issues were detected by me.

And each time when I had tried to execute something like

temp = ETH_ReadPHYRegister(0x01, 0x02);

I got only 0x0000FFFF.

Note. There is no clocking at 25 pin.

Oscilloscope shows me the STM32F407VET6 toggles MDC and MCIO lines, but DP83848CVV does not responding. I saw only 3.3V level (that means 0x1111).

How to check if the IC was not damaged?

Help, please. I gave up the attempt in despair.

over 11 years ago

0 John Griffith over 11 years ago

TI__Mastermind 21471 points

Hi Vladmir,

I moved you question to this forum so that the proper people can help you with it. Please post your future Ethernet questions in the forum.

Thanks!

John

0 Patrick OFarrell over 11 years ago in reply to John Griffith

TI__Mastermind 31600 points

Could you clarify the clocking for the device? You mention a 50MHz RMII clock and a 25MHz crystal. Which of these are connected to the reference clock input of the DP83848?

Patrick

0 Vladimir Shein over 11 years ago in reply to Patrick OFarrell

Prodigy 85 points

Many thanks Patrick for your attention to my problem.

This is ethernet phy part of my schematic:

and the part where ETH_RMII_REF_CLK is connected. The clock is 50 MHz (as I can see with oscilloscope).

Many thanks.

UPD: The case temperature of the IC is about 40°C(104°F). This "measurement" was done by my finger but of course I can measure it more precisely if this information is actually required and will help clarify the situation. The IC is soldered in right position and I can provide a photo to prove the words.

UPD2: The photo (with flux residue)

Note: This is just PCB for development. Its layout is not optimal and I know this. In release version I'll fix all founded issues. PCB has 4 layers.

0 Vladimir Shein over 11 years ago in reply to John Griffith

Prodigy 85 points

Many thanks, John! :)

0 Vladimir Shein over 11 years ago in reply to Patrick OFarrell

Prodigy 85 points

Patrick, I am pinning all my hopes on you. I am taking delivery with my new dp83848ivv and KXO 97T (50MHz) next Tuesday.

0 Patrick OFarrell over 11 years ago in reply to Vladimir Shein

TI__Mastermind 31600 points

Vladimir,

In the schematic, it does not appear that PFBOUT is connected to PFBIN1 or PFBIN2. Could you please confirm these voltages on the board? If they are not connected, you should wire in these connections and see if that resolves your issue.

The PFBOUT pin should provide a 1.8V output. That 1.8V powers on-chip circuitry via the PFBIN1 and PFBIN2 pins. If you are not seeing 1.8V on these pins, then that should be the primary focus of debug. Until this 1.8V supply is operating correctly, the device will not operate correctly.

Patrick

0 Vladimir Shein over 11 years ago in reply to Patrick OFarrell

Prodigy 85 points

THANKS A LOT, Patrick!!! You are my SAVIOR! This issue was my mistake :( Now the dp83848 is working as expected and I can start debug my firmware. :)

Many, many, many THANKS!!! :)

Best regards

Vladimir Shein

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DP83848 and STM32F407VET6 no communication.