Kinetis MicrocontrollersのトピックRe: K20 USB low-level communication

K20 USB low-level communication

stevea — Mon, 16 Dec 2013 22:11:30 GMT

Greetings All,

I am working on a project with the MK20DX256VLL7 processor. I have been able to successfully run the FSL_USB_Stack on our custom board using the CDC device (many thanks to BlackNight ). I also have been able to communicate with a host PC using a virtual comm port.

However, I need to design this project so that several devices can be connected to a host PC at the same time, and I'd like the user to not have to worry about the specifics of comm ports and the way that Windows auto-increments the number with each new device. Is the CDC device appropriate for this task, and if so, what driver do I need to call in the .INF file? Is there perhaps a better device class to use? We are starting to look at an FTDI chip and driver set, but that seems a little silly considering the K20 already has USB capabilities.

Regards,

--steve

Re: K20 USB low-level communication

perlam_i_au — Tue, 07 Jan 2014 23:20:21 GMT

I think as well as you that CDC is the best USB class option for your project, but regard COM enumeration while connecting different devices I suggest you to check on specific documentation of USB.org - Approved Device Class Document Download, Enumeration of USB Composite Devices (Windows Drivers) and Enumeration of Interfaces on USB Composite Devices (Windows Drivers).

I hope you find this useful.

Re: K20 USB low-level communication

bobpaddock — Thu, 09 Jan 2014 15:50:29 GMT

I just posted some code to show what COM ports match what USB device:

"How to display com# when USB is plugged in?"

I got tired of answering the support question "What COM port do I have?".

Poking at the registry to prevent the COM port from changing is a dubious process across all the versions of Windows.

Far safer to just use the SetupAPI's as the above link shows.

Re: K20 USB low-level communication

stevea — Fri, 10 Jan 2014 16:33:28 GMT

Thanks for this. It looks useful, I'll give it a try.

I found a similar project in VB by J.Axelson at http://www.lvr.com/serport.htm#example_code

The code uses the command SerialPort.GetPortNames to get the currently used ports (not necessarily open).

--steve

Re: K20 USB low-level communication

Teckna — Wed, 05 Nov 2014 10:03:04 GMT

Hi Bob,

I can't see the link, it seems broken.

Many thanks

Teckna

Re: K20 USB low-level communication

johnstrohm — Wed, 19 Nov 2014 21:53:26 GMT

It appears that www.lvr.com has been hijacked or otherwise taken over by a retailer, www.luisaviaroma.com, which may or may not be legitimate.

Re: K20 USB low-level communication

bobpaddock — Mon, 01 Dec 2014 16:19:01 GMT

lvr.com is now: http://janaxelson.com/

Re: K20 USB low-level communication

bobpaddock — Mon, 01 Dec 2014 16:21:04 GMT

http://www.janaxelson.com/forum/index.php?topic=1239.0;wap2

lvr.com is now janaxelson.com