µVISION DEBUGGER: Cannot connect to J-Link via USB.
Information in this knowledgebase article applies to:
When I try to debug an ARM7/9 device with the µVision Debugger via J-Link, starting a debug session or a flash download always fails with the following message in the Build Output window:
Cannot connect to J-Link via USB.
The J-Link device is probably configured for a J-Link USB ID other than 0. Due to that, it can't be recognized by the µVision J-Link Debugger driver used for ARM7/9 devices.
Configure the J-Link for USB ID 0. This can be done with the J-Link commander tool found in the MDK-ARM installation directory C:\Keil\ARM\Segger\JLink.exe. This will identify the J-Link with ID different than 0 and when connected, provides a command "usbaddr" to change the ID:
C:\Keil\ARM\Segger>jlink SEGGER J-Link Commander V4.36l ('?' for help) Compiled Dec 2 2011 18:52:52 DLL version V4.40c, compiled Jan 24 2012 09:30:33 Firmware: J-Link ARM V6 compiled Feb 1 2011 14:28:14 Hardware: V6.00 S/N: ******** Feature(s): FlashBP, FlashDL J-Link>usb 0 /* old style: J-Link>usbaddr=0 */ USB address successfully changed to '0'. Please unplug the device, then plug it back in. J-Link>
After reconnecting the J-Link unit to the PC, debugging the ARM7/9 device with J-Link via the µVision Debugger should work.
Please note that the µVision J-Link Debugger driver used for Cortex-M devices has the ability to use J-Link adapters with different USB IDs. The ID can also be changed with J-Link Setup dialog.
The following Discussion Forum threads may provide information related to this topic.
Last Reviewed: Monday, September 26, 2016
of your data.