Forum : ARM
Original Post
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April 17, 2009 - 10:05am
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Hi! I've encounterd some problem with USB on STM32. I create project that base on new ARM library (3.0.0) and use Virtual COM Port Example. All works fine when i connect my board through the notebook or directly to the Desktop PC with Windows XP & Vista. But when i connect directly to Notebook (Windows or linux - doesn't matter) or to Desktop PC with linux - system cannot fint this device. In Linux kernel throw error -71. The same Example works fine on ST evaluation board with STM32F103ZET. If any one have any idea why my board doesn't work correctly on all platforms? Best Regards |
Hi
I am not sure I understand the description of your issue.
Can you clarify listing which configuration is working and which one is not.
Regards,
Matloub
Ok.
Connected directly to the notebook (any system) - doesn't work
Connected directly to the DesktopPC with windows Vista & windows XP - work perfect
Connected to the notebook through USB Hub (windows linux - doesnt matter) - work perfect
Connected directly to the DesktopPC with linux - depends. on some machine work, on some doesn't, but always work when connected through the USB Hub.
Regards
Maciej
Hi,
At first glance, I would say this is a problem with power supply.
Notebooks sometimes have weaker power outputs on USB ports. (internal HUBs, ...)
And the OS also plays its part in configuring the USB ports power outputs.
Is your board powered by USB or external power?
Is your HUB powered by USB or external power?
Does your board provide a jumper or protection diode that you could use to place an amperemeter to measure the current that your board pulls on the USB 5V in the different situations? If not you can do that by opening a USB cable and cutting the red wire. (and that will allow you to measure the current pulled by the ST Eval board for comparing. ;) )
I hope it helps.
Best Regards,
Vincent