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LPCXpresso LPC1343 board bootloader not recognized by PC USB port

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LPCXpresso LPC1343 board bootloader not recognized by PC USB port

‎06-15-2016 05:21 PM
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lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by CC58 on Sat May 26 11:48:42 MST 2012
I acquired a LPCXpresso LPC1343 board. It works fine with compiler/debugger using supplied USB connector.  I want to execute ROM based bootloader so wired up a second USB connector and connected PIO0_1 to GND, connected PIO0_3 to VDD.  Added 1.5K pullup resistor from USB_DP to VDD.  PC says unrecognized device no matter how many times I plug it in.  Tried two PCs; Windows7 and XP.

Out of frustration I bought a second LPC1343 board and it does not work either.

This should be easy.  What am I doing wrong?

:(
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‎06-15-2016 05:21 PM
917 Views
lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by CC58 on Tue Jun 12 14:05:02 MST 2012
Tried the Soft Connect circuit, but still had problem.  Then ran across AN10904 that shows USB pinout.  I had USB polarity wrong.  Used a pinout found on internet site. My bad. Can see USB drive on PC now.
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‎06-15-2016 05:21 PM
917 Views
lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by gbm on Sat May 26 23:33:21 MST 2012
Read the LPC134x errata on USB loader. There is a problem with uninitialized variable. Extra time or software intervention is required for the loader to run.
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‎06-15-2016 05:21 PM
917 Views
lpcware
NXP Employee
NXP Employee
Content originally posted in LPCWare by Ex-Zero on Sat May 26 14:48:37 MST 2012
LPCXpressoGettingStarted:
Quote:

Note: This simple connection does not implement NXP Soft-Connect to allow soft disconnection and connection to the USB bus. Because of this, the USB connection must be plugged into the PC near the time the USB peripheral is initialized, or after. If the USB port is connected when the LPC USB peripheral is not initialized, the pullup resistor will notify the PC that a USB device is present, yet the microcontroller will not respond because it has not been initialized. This will trigger windows to generate an error regarding a malfunctioning USB device. Unplug and re-plug the device to dismiss the error.
I would strongly recommend to use a FET to switch D+ pullup.

Schematic: http://flic.kr/p/9eHZfj
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