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All: I have the HTTP_demo working perfectly on the MCB2300. I have designed my own board so that its Ethernet is hooked up exactly the same as the MCB, same PHY, same connector, same everything. The plan was that the code could be developed and tested on the MCB, then simply moved to the new board. I took great care in layout and verifying all the connections. But the code doesn't work on my board. In fact, the PHY is acting very strangely. On the MCB, pins 1,2, 3 and 6 all appear to have signal about +/- 1V P-P around 3.3V. On my board, 3 and 6 have a similar waveform but it goes from about 1 to 4.5V, much more energetic. And 1,2 are flatlined. More interesting is if the Ethernet connector is removed, on the MCB 1,2,3,6 are flatlined as you'd expect, but on my board I get flatline on 1 and 2 and 3 and 6 still have the energetic waveform. There has got to be something simple I'm missing. If you know the Ethernet on the MCB2300 and can help, respond to this thread or send an email to daver@birket.com and I can send you schematic, scope traces, etc. I'm fresh out of ideas on how to tackle this one.
> In fact, the PHY is acting very strangely. On the MCB, pins 1,2, 3 and 6 all appear to have signal about +/- 1V P-P around 3.3V. On my board, 3 and 6 have a similar waveform but it goes from about 1 to 4.5V, much more energetic. And 1,2 are flatlined.
Sound like you are talking about signals on the magnetics pins, instead of the PHY chip. MCB2300 board mounts J0011D21B of Pulse Electronics Corporation productfinder.pulseeng.com/.../J403.pdf
Did you select pin-compatible magnetics for your board? You may use any magnetics of RX/TX 1:1 with CT, but pin assignments are different from magnetics to magnetics. Check the pin assignments of your magnetics.
Tsuneo
Thank your for your help, I'm using the exact same part as on the MCB board. yes, i was talking about the port pins, on the PHY chip they're the RD+, RD-, TX+, TX- Ethernet signal pins. The question is what could cause the PHY to be outputting such a signal?
Ah, I see, ponder on your problem a little deeper.
1) Power feedback pins On the MCB2300 schematic, http://www.keil.com/mcb2300/mcb2300-schematics.pdf connections across power feedback pins, PFBOUT (pin 23) - PFBIN1/2 (pin 18/37), of DP83848 are not obvious. These pins should be tied together. Does your board have these connections?
2) Interpretation of your signal monitoring > On my board, 3 and 6 have a similar waveform but it goes from about 1 to 4.5V, much more energetic. And 1,2 are flatlined. .. if the Ethernet connector is removed, ..., but on my board I get flatline on 1 and 2 and 3 and 6 still have the energetic waveform.
The "energetic" waveform should be FLP (Fast Link Pulse) burst of auto-negotiation at the start of link. These pulses have greater voltage swing than usual packets. This Ethernet PHY, DP83848, keeps trying negotiation.
Your description at disconnection is not clear, but maybe, 1 and 2 (TX) - flat line, 3 and 6 (RX) have waveform ;-) The PHY chip has MDIX capability, which swaps TX and RX ports for cross-connection. Sound like this function is applied on the chip.
Disabling auto-negotiation and MDIX may give another clue of your problem.