Difference between revisions of "J-Link no USB enumeration"
(→J-Link USB Isolator in between) |
|||
Line 12: | Line 12: | ||
[[File:24JLinks_USB30.png]] |
[[File:24JLinks_USB30.png]] |
||
− | == Sample setup |
+ | == Sample setup workarounds == |
− | The following shows |
+ | The following shows different sample setups which workaround the problem and let Windows enumerate all J-Links. |
+ | |||
+ | === Workaround 1 === |
||
+ | Eliminate the first level USB 3.0 hub and connect the other hubs directly to the PC: |
||
+ | |||
+ | [[File:24JLinks_USB30_WorkAround1.png]] |
||
+ | |||
+ | === Workaround 2 === |
||
+ | Use a USB 2.0 hub instead of the first level USB 3.0 hub: |
||
[[File:24JLinks_USB2.png]] |
[[File:24JLinks_USB2.png]] |
Latest revision as of 10:02, 14 May 2018
Contents
Max. 10 J-Links enumerate
When connecting multiple J-Links to USB 3.0 ports + hubs, it can happen that Windows only enumerates up to 10 J-Links and then throw enumeration errors. Depending on the USB setup, it may also be only 8 or 9 J-Links that are enumerated. This is not a problem in the J-Link USB driver, but a limitation of the USB 3.0 controller, as the error message indicates:
Sample setup with error
The following shows a sample setup which produces such an error
Sample setup workarounds
The following shows different sample setups which workaround the problem and let Windows enumerate all J-Links.
Workaround 1
Eliminate the first level USB 3.0 hub and connect the other hubs directly to the PC:
Workaround 2
Use a USB 2.0 hub instead of the first level USB 3.0 hub:
Connection lost on firmware update
J-Link USB Isolator in between
When issuing a firmware update and having J-Link connected to the PC via a J-Link USB Isolator, on some specific models it can happen that communication is lost on firmware update. This is due to a bootloader problem in these devices that unfortunately cannot be fixed via a firmware update. For these J-Links, firmware updates should be applied with no USB Isolator in between. After the firmware update has been successfully performed, the USB Isolator can be used again.
Affected J-Links:
- J-Link PRO V4
- J-Link ULTRA+ V4