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AM1808 - NO ETH PHY

Other Parts Discussed in Thread: AM1808, CODECOMPOSER

Not sure if this is a question for this forum or the development area...but hopefully someone has some suggestions. We are trying to get a custom board up and running that uses all of the same pieces as the AM1808 Experimenter Kit setup (same TI AM1808 processor, Same PHY, Same NAND (from sister board)). Anyhow, I have been able to flash the NAND with the version of U-Boot I am using on the experimenter kit setup.  When I boot our custom board, however, I receive an error message that "NO ETH PHY DETECTED".  After much research...I ran the Board System Level (BSL) test for "Emac Loopback MII Test" via my blackhawk USB100v2 emulator (and CodeComposer) and all tests passed.  It finds an active phy: 0x00000001,  It performs the loopback test successfully transmitting and receiving a packet.  So...apparently not a hardware problem..which leads me to believe it is a configuration problem. I have set an ethernet MAC address using U-BOOT parameters and have attempted same boot cmd and boot args that were used on the experimenter kit board (that works on the experimenter kit setup).  Anyone have any suggestions on how to force u-boot to recognize the PHY?  Of course running the uboot command "mii devices" returns nothing because according to uboot the phy does not exist.  Where do I go from here?

Thanks in advance for any suggestions.

  • BUMP - Any T.I. tech out there that can make some suggestions as to why when I run the BSL test "Emac Loopback MII Test" everything passes...but uboot can't find the PHY?  As stated above...custom board has same components as the experimental board. Uboot is configured to run out of NAND. I need some help on this...please respond if you have any ideas.  Thanks!

  • Problem solved - turned out to be a hardware design issue which was only found after careful scrutiny between our custom board and the experimental kit board.  The problem was a missing 1K pull down on Buffer OEn.