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Kinetis K22 USB Latency Test

Question asked by Nick Guzzardo on Jul 18, 2018

I am brand new to USB in embedded systems.  I have the TWR-K22F120M tower board and have been able to run example code from the SDK within MCUXpresso for HID and CDC VCOM, but I'd like some pointers to take these examples into my own code base.

 

My current task is to connect my tower board to a PC via USB, transmit n-bytes of ASCII data from the PC to the tower board and back in order to measure net latency and determine repeatability over m-iterations.  We intend to vary the number of bytes as well as add some processing of the transmitted data on the tower board to determine impact, but for now I just need to control transmitting and receiving data.

 

The other part of the struggle I'm having is that we want to avoid the use of VCOM as I believe we wouldn't have access to full-speed USB data rates (correct me if this assumption is incorrect).

 

I would like to setup a simple set of bulk end-points to which I send and receive data.  We will add the timing functions on the PC side.

 

I have been scouring the internet for intro training and have found some good info regarding USB generically, but not specific to basic USB development much less development of USB CDC devices for Kinetis K22!

 

If anyone can help get me started it would be greatly appreciated.

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