LAUNCHXL2-RM46: XL2 dev board not working correctly

Simen Skrlep

Part Number: LAUNCHXL2-RM46
Other Parts Discussed in Thread: LM26420

Hi!

My XL2-RM46 dev board stopped working after trying to connect it with a Ethernet PHY. When I connect the USB cable the LEDs 4 and 6 are only half-lit and there is a high piched noice comming from the board. I cannot connect to it. The voltage from the USB is ok, but the output voltage of the board is halved. It stays the same even when reset or pugged/unplugged. Any idea what's going on?

over 6 years ago

0 QJ Wang over 6 years ago

TI__Guru**** 190426 points

Hi Simen,

Do you connect the Ethernet PHY to the launchpad through blue wires? or your Ethernet PHY daughter card has the same connectors as J10/J11 on launchpad?

The J10 has power supplies (5V and 3.3V) and Ground, and they are next to each other. I guess the 3.3V power supply is shorted to GND somehow.

0 Simen Skrlep over 6 years ago in reply to QJ Wang

Prodigy 50 points

Hi, QJ!

I use a custom PHY with LAN8720, connected to the board with jumper wires. But I don't think that's the problem, since the board is behaving this way even when nothing is plugged on it. And the custom PHY works fine with the spare board.

I did have initial problems connecting PHY's nRST pin - i connected it with Hercules_nRST (J10, p22), but that prevented the program to load to the board. I might have messed up there, since the board went catatonic not right away but shortly after that.

0 QJ Wang over 6 years ago in reply to Simen Skrlep

TI__Guru**** 190426 points

Hi Simen,

If your PHY EVM is powered by LaunchPad through blue wire, it is possible to short 3.3V or 5V to GND accidentelly. Can you connect to Launchpad after you disconnect PHY EVM and LaunchPad?