Part Number: DP83TC817S-Q1
I am facing an issue with setting up communication between two devices communicating over 100Base-T1 Ethernet. In normal mode, a link can be establish between one of our devices and the custom board with our MCU and DP83TC817-Q1, but we cannot get any further communication to work.
Our board is set up for MII full-duplex mode between the MAC and PHY and we can configure the PHY over the MDIO interface.
To rule out the MAC-PHY connection issues on the custom board, we are trying to attempt MII, PCS, Digital, and Analog loopback modes before trying to test the MDI/cable connection side. For simplicity we are attempting this without the PRBS. We succeed with MII loopback, but cannot get data back when in PCS mode.
According to the manual that I have, we are setting BIST control reg to 0x102 for PCS loopback. We can see activity on an oscillope on the TXD lines and TX packet count register is showing increase in packets received, none with CRC errors. However, no activity on the RXD lines.
The current steps I take:
- Reset the PHY (wait recommended amount)
- Take it out of standby mode and into normal
- Set into slave mode
- Config LEDs to show TX/RX activity and link OK
- Enable PCS loopback
The DP83TC817S-Q1 PHY is bootstrapped to autonomous mode enabled, master mode (which we change to slave), and MAC interface set to MII.
Is there anything that I am missing or something that differs in settings between MII and PCS loopback that explains this behavior?
Thank you in advance!