USB Device not recognized, LPC1347

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by jab on Thu Sep 13 09:05:00 MST 2012

We have designed a custom board around the LPC1347. One of the features of this board is that if plugged in over USB and set into program mode the device pops up as a USB mass storage device so you can drag and drop your programming file.

Our board enumerates okay if the board is plugged into a USB hub but not directly into the computer. The User manual and data sheet recommended a 33 ohm resistor in series with each of the USB Data lines but this causes the device not to enumerate at all. With those resistors replaced with 0 ohm resistors it enumerates but only when plugged into a USB hub (powered or unpowered).

Has anyone else experienced this?