UART to female USB 3.0?

Hey everyone,

Can I take the UART J17 connector and plug in a UART to USB 3.0 (or even usb2.0) FEMALE connector?

I’ve found tons of UART to usb on ebay and even found UART to usb micro but can’t find any UART to standard size female usb?

Do I have to do UART to male usb and then put a female to female connector on there?

All I want to do was get another female USB 3.0 full size connector on the board for peripherals. How do I make this happen?

Also I’m looking on page 26 of the Carrier board specifications and trying to find out what voltages are on the uart. Does it to both 3V and 5V? Just want to make sure I plug everything in correctly and don’t hurt my baby.


Mostly I’m seeing stuff that looks like this

Do they make something like that has a female instead of a male USB? Or do you just have to use a female to female converter?

Can I use something like this

and then put a female to female connector on it?

Is UART on the board 3.3V or 5V?

Default logic level on J17 header is 3.3V. There is a jumper, J24, which can optionally be set to 1.8V instead (this sets some others to 1.8V too if you change it from the default 3.3V setting).

Here’s a typical compatible serial to USB UART running at 3.3V:

Interesting, so the other ones I posted are devices going the other way? Like to plug into a USB female on a pc to give you access to serial/uart?

also is there a cable like that digikey one that goes to female usb? Or does everything only go to male?

I’m not positive on the serial UART plug combination you want, so I’ll describe some things for USB plugs and then perhaps it’ll be easier to ask (it’s amazing to see what detail is needed for such a simple question). All of this excludes talking about newer USB3 connector type-C (Jetson has USB3 speed in some configurations, but Jetson does not physically have a USB3 type-C connector…the Jetson connector is a backwards compatible USB2 type connector which can function at USB3 speeds).

Hosts (including desktop computers and Jetsons) always have a female type-A USB connector if a device can be plugged into it (such as keyboard, mouse). This is true regardless of being full-size or micro-size.

Devices (such as printer, keyboard or mouse) always have a female type-B connector, or a hard wired equivalent straight to a cable (mice usually solder a cable instead of using a connector, but they could use a type-B connector). This is true regardless of being full-size, micro-size, or equivalent hard wired via solder to a cable.

Cables are ultimately always between a host and a device. Cables which are not hard wired with solder are almost always male at both ends, but type-A at one end and type-B at the other end. If the cable has male type-A at one end and female type-A at the other end, it is an extension cable and not used directly between a host and device…because of the cable that the extension plugs into, the result will still be type-A at one end and type-B at the other end.

OTG is special because depending on cable type-A or type-B the software will detect cable type and switch mode and hardware between host (if type-A is inserted) and device (if type-B is inserted) behavior. Because the OTG can be only host or device at any one time rules of type-A and type-B are still true. The micro-USB cable which a Jetson ships with has a type-B connector which is valid when Jetson is a device…a.k.a., recovery mode for flashing. For a HUB and other devices to connect and function on this port during normal non-flash operation, the cable has to instead be a type-A micro USB connector. You may have a short adapter which is an extension cord simultaneously going from full-size to micro-size. Look very closely at the micro connector on the short extension and compare it to the micro connector of the longer cable…there are very slight differences in their shape which can be used to detect which type is plugged into the OTG port.

A serial UART cable is a device at the USB side. If a USB cable is not hard wired to this, then the device side connector type must be type-B (micro or full-size) female. When a cable is hard wired to this device, the loose cable end must be male type-A. The devices you gave URLs to are simply hard wired with a cable length near zero, and the male connector is the loose end of the near-zero-length cable.

The serial port end of the adapter has no connector requirements, one can use loose wires or nice plugs/sockets. Sometimes only three of the six wires are used. Often 5 of the 6 wires are used when a nice connector is involved (the two extra wires would provide hardware flow control). The sixth wire could be used to draw 5V power from the USB connector of the host, but this is irrelevant for a Jetson (which is already powered). So long as the interface voltage of the serial UART and the serial port are compatible, most anything works. Default level on the JTX1 serial UARTs is 3.3V (there is a jumper which can alter this to 1.8V).

Are you looking for different USB ends, or are you looking for different connectors at the UART end? Most of the options available are for interface voltage or for the non-USB UART end.

Wow that is rather complex, I thought it was complex, but it’s even more complex that I imagined. There is actually a lot of background to know about this.

All I was looking to do was to take the UART pins on the Tx1 and through some cable create a female type-A USB connector so as to have a second additional female type-A USB connector available. Perhaps even plug a usb hub into that female connector. Can this be done on the default 3.3V UART pins?

btw… thank you for the background and the help.

It would be great if there is a cable that goes to Female type A but failing finding that would something like this work?

I’m trying in the end to get something that looks like this that I can plug a device into like a USB thumb drive or other usb device

The UART will not function as a USB connection, in part because it is incapable of going even the tiniest fraction as fast as needed for most USB. With a lot of hardware and software work it could be adapted to work as a low speed USB1.1 for something like a keyboard.

If you were to build your own, you’d end up using the GPIO instead of the serial UART…the UART is much too slow. You would have to know a lot about the kernel’s software, and create custom hardware designed around something like this:

One issue is that the UART is not a differential pair as used by the USB. In cases where one of those simple adapters exist you essentially have something like the chip I linked above to provide the D+/D- data differential pair integrated into the board…it is serial, but it isn’t a serial UART and it isn’t TTL level.

You could add a PCIe USB port card. This isn’t as compact, but it is basically as simple as it would get if you’re not simply adding a bigger HUB to the existing ports.

On the related Jetson TK1 there is a mini-PCIe slot which does route an extra D+/D- data lane that would let you provide a USB port on a custom mini-PCIe card, but this does not exist on the JTX1. On desktop motherboards the 4-pin headers of a USB2 connector would contain ground, +5V, and a D+/D- differential pair for the data. None of the headers on a JTX1 are suitable for a simple direct connect USB socket scheme.

Thank you for clearing that up and for helping me with alternatives. Using the PCIe 4x port isn’t really an option because I want to use a different card there. I guess i"ll just let it go. Thanks for the help,