Question OTG usb to PC power

[emantec]

I have a proprietary embedded device which is running a MCIMX6U5EVM10AC - NXP(freescale) i.MX 6 series 32-bit MPU, Dual ARM Cortex-A9 core, 1GHz CPU.

I'm trying to find the serial port and so far have failed, there are multiple unpopulated jacks on the board all of which do not appear to be serial connectors. further research suggests that it is actually implemented via USB to UART - see page 5 here https://cache.freescale.com/files/32bit/doc/quick_start_guide/IMX6SL_EVK_QSG.pdf

However, it would appear this is a powered OTG port, checking the vbus shows there is 5v being provided, I don't know much about USB's and the google results seem to be very conflicting but surely if I connect this to my PC something is going to melt? The PC will surely try to power the device and it's already trying to provide power itself.

Any help on this would be appreciated.

 

[OldSurferDude]

It looks to me that one would use the "USB to UART Connector" when connecting to a PC. A new com port will appear in your list of devices (W10 see "device manager"; linux "ls /dev") This would appear to be what the programming software on the PC would use. You could probably also use hyperterm (W10) or minicom (linux) to communicate over this port, though you'd have to know what commands your device would be expecting, (in addition to the serial parameters BAUD, bits, start, stop, handshake)

USB OTG is for a USB device or powered USB hub. It looks like the "USB host" functions similarly.

I hope you have a lot more documentation than the QSG. And a lot of time, patience, perseverance, and a more appropriate and helpful support website than Tom's Hardware. You're taking a big bite of something on the fringe. Would not an RPi work as well?

 

[Alabalcho]

Page 6, Item #3: What is not clear there? You connect a microUSB cable here, plug into a PC, install FTDI driver if necessary, find out which COM port it links to, open HyperTerminal / Putty - voila, you have a console!

Of course, the OS which boots should have proper configuration to enable this port.

 

[emantec]

Probably should have mentioned this is a retail board, not a development one, none of these headers are populated.

Its simply not that straight forward when there's no actual micro USB port, I've just tested the pins and come to the conclusion it must be one considering it's 5v, 2 data lines and a ground.

I'm on the side of caution and would rather not melt the thing by plugging it into a pc to find it was a host USB and was designed to hold a sd card or something. As I mentioned before, if its meant to connect to the pc surely the vbus wouldn't have 5v running through it?

If you know of a better site to ask this question let me know, Google wasn't particularly helpful in finding a relevant forum for hardware hacking.

Here's a labelled picture to show what I'm working with

 

[Alabalcho]

"Better site" would be either NXP forums, or that board' vendor. "OTG" port would normally be used to plug an USB device (flash disk) to be accessed by the board, not into a PC.