topic How to turn off USB block. in Kinetis Microcontrollers

How to turn off USB block.

CCandido — Tue, 20 Jun 2017 12:48:25 GMT

How to turn off USB block.
Need to turn off usb complete, without unplugging cable, and without resetting the processor.
I need to use same usb cable for two usb processor.

I made a few attempts but when you hang up, you will not call later.
I need to turn it off and on.

I have an application on (PC) that chooses and controls which device to use.

Processor: MK20

USB Stack 4.1.1 (cdc)

IDE: KDS- V3

Thanks,

Carlos.

Re: How to turn off USB block.

stephanie_m — Tue, 04 Jul 2017 23:56:57 GMT

Dear Carlos Candido,

One of the things I would like to mention it’s the fact that in the USB communication the host it’s the one in charge of managing the devices and descriptors; for that reason, the device cannot perform a detach by itself.

The host it’s who can send a BUS RESET command to the reset of the end devices; in any case of a disconnection or reset the re-enumeration can’t be left behind, it will always need to re-enumerate the device.

One approach it’s to add a transistor in the VBUS connection, as the D+ / D- lines resistors are hung up to them, this transistor will be controlled by a GPIO acting as a switch by doing this the host will acknowledge this as a detach.

Best Regards,

Estephania

Re: How to turn off USB block.

CCandido — Mon, 17 Jul 2017 15:27:43 GMT

Hi, Estephania

I had not thought of it that way,

I'm going to take a test.

thanks,

Carlos.