No COM port appeared after connecting the TWR-POS-K81 via USB to a Windows 7 (64-bit) PC! And instead of "MSD_CDC_device" (as described in the Quick Start Guide) showing in Other Devices in the Device Manager, "MCU Virtual Com Demo" appeared instead.
When I right click on the MCU VIRTUAL COM DEMO device, select "Update Driver Software ...", select "Browse my computer for driver software ...", then input "...\boards\twrk81f150m\usb_examples\usb_device_cdc_vcom\inf" as the folder to search (as suggested in some NXP Community post), I get the error "Windows was unable to install your MCU VIRTUAL COM DEMO Windows could not find driver software for your device ...".
Where is the driver for MCU VIRTUAL COM DEMO for the TWR-POS-K81?
That did not help. I had already seen that post and had tried all available vcom inf folders/files available on the machine. Evidently something has changed on the TWR-POS-K81 board that has a different/new virtual com and requires a different driver than has been working with previous boards/kits.
There shouldn't be any difference in the TWR-POS-K81, I tried it with a Windows 10 and a Windows7 64 bit and in both cases, It was recognized. Have you tried the option
"click in Let me pick from a list of device drivers on my computer and In manufacturer select Freescale and Model Virtual Com Port"
of the post?
What Other drivers did you have listed here? you could look also for NXP VCom drivers.
It is working this morning!
The SDK that builds in MCUXpresso SDK builder for the twr K81 is 2.4.1, which has no virtual com drivers for the twr K81.
I loaded the Kinetis SDK 1.3.0 (from both the "Kinetis SDK 1.3.0 Mainline - Windows.exe" and the "Kinetis SDK 1.3.0 Standalone for the FRDM-K82F - Windows.zip") which both have the "...\demo_apps\usb\device\cdc\virtual_com\inf\fsl_ucwxp.inf" driver which works with the twr K81.
Seems like the SDK that builds online for the twr K81 should include the driver!!!
Thanks for pushing me onward to find the solution.