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NXP^TM M522XX, KINETIS and i.MX RT / A USB problem

« on: February 05, 2010, 12:32:25 AM »

Mark,

While doing USB stability test for my project, I have this subtle but very consistent problem.
I have a task that sends same size data (4 - 300 bytes depending on setting) to a PC through USB every 0.1 s.

It runs OK for days, if data size is small (probably < 64 byte) OR Ethernet is not connected.
When data size is bigger AND Ethernet is connected to the LAN, the USB communication hangs in a few hours.

It happens with no active Ehternet communication other than broadcasts from a switch.
There are UART communication is going on all the time, but it does not seem to cause any problem.

My guess is somehow Ethernet interrupts, taking place while the USB stack prepares the second or subsequent packets, may cause a problem.

How can I find a clue for this problem?

Chuck

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NXP^TM M522XX, KINETIS and i.MX RT / How do I change hardware handshake lines in USB CDC?

« on: January 06, 2010, 12:42:52 AM »

Hi Mark,

I use USB CDC for serial communication emulation with 52259. It works great so far, and I want to have more control on hardware handshake lines for flow control. I can see how to update RTS and DTR lines from the host in control_callback function.

How can I send changes in CTS and DSR lines to the host? What do I write into USB_control end point?

Chuck