Other Parts Discussed in Thread: PROFIBUS, DP83848I
Hi, I am trying to implement 10/100 mb/s ethernet with M12 profinet connector on my board.
This is my second set of PCB's. In first set, there was problems with level shifting on the RMII signals. Now i have working RMII and MDIO. I tested this by setting the loopback bit on at BMCR, then sent and received a frame.
PHY and all it's schematic has stay'd the same.
For some reason i can not get this to link to another device. I tested the older version of the board too, no linking.
Here is the schematic for the phy:
Here is the schematic for the magnetics and the connector
I have first soldered the DAP on with hot air soldering station, then connected all the pins with soldering iron under microscope.
I soldered an LED to AN0 pin according to datasheet for debugging the linking.
This does not affect my autonegotiation strapping, since AN0 pin is set to 1 by default. In my case its unconnected.
When install jumpers from TX+ to RX+ and TX- to RX- on the M12 connector ( external loopback), and the LED turns on, indicating that link is established.
When i connect the board to my laptop with profibus cable and RJ45 crossover adapter, the link is not established. The led wont turn on, and the ethernet adapter says cable unplugged.
After disconnecting the the board from my PC, i connected oscilloscope to TX+ and TX- pins of the M12 connector on the board.
I see positive Fast Link Pulses, but it is not sending the same message constantly. Its really messy and changing constantly.
Here is an video of oscilloscope view:
I am all out of ideas where to debug. Please take a look on the schematic. i can not spot a mistake in there.
I also have one of these waveshare DP83848I modules. When i give power to this, and connect this to my laptop i get link instanty. With or without crossover adapter.
Here is a schematic for this module.
DP83848-Ethernet-Board-Schematic.pdf
I can take measurements from this, if needed.
Thank you in advance,
Jani Järvenpää