The bidirectional USB 3 Mux allows either a single USB device (or multiple devices when using a USB hub) to be switched between two USB hosts (computer) or using its bidirectional ability you can connect one of two devices to a USB host at a time.

Features

• Supports USB 3 and USB 2.
• Bidirectional (switch 1 device to 2 hosts or 2 devices to 1 host).
• Switches both data and power between A<>B and A<>C.
• Power line disconnected for unselected port.
• Power on Delay when switching port (giving the device time to reset).

There are three USB3 Type-A sockets on the multiplexer labelled A, B, and C. The multiplexer can be toggled between connecting port A to B when pulling the S pin LOW (default) or connect port A to C when pulling the S pin HIGH (using a 3.3V to 5V signal).

The 3-pin 0.1" header has pins for GND, S, and 3v3 which can be used to connect a manual switch if required or you can connect the GND and S pins to a microcontroller to switch ports.

Whilst there are many USB 3 Multiplexers available to share a device between USB hosts and some of these are capable of bidirectional use they rarely switch the power (i.e. other bidirectional multiplexers simply connect the power pins of all USB ports together which can confuse a USB device when when its data lines are connected to a different USB host). With this multiplexer the power is switched so when selecting A<>B either port can source power for the other but port C is not powered, similarly when using A<>C either port can supply power for the other but port B is not powered.

Another feature of this multiplexer is a power delay. When switching from A<>B to A<>C by pulling the S pin HIGH power is first disconnected between A<>B and the data lines are connected between ports A<>C. Then after a short delay the power is connected between A<>C (and vice versa when S goes LOW). Delaying the power like this when switching gives the USB device time to reset.

To control which USB host the USB port is connected to, set the S (SELECT) pins HIGH/LOW as per the table below (the S pin works with a 3.3V to 5V signal).

The PCB is designed to fit onto the (USB/NIC end) mounting holes of a full sized Raspberry Pi with 40-pin header. This allows easy stacking when using the multiplexer with a Raspberry Pi.

Only suitable for 5V supplies with 5V devices.

Compatible Cables

When using the Multiplexer you will normally need to use USB 3 Type-A plug to Type-A plug cables. For example you would need two plug<>plug cables to share a USB Flash drive between two computers or one plug<>plug cable to switch between two USB Flash drives on a computer.

Compatible 1m USB3 Type-A plug to Type-A plug cable(s) can be ordered with the Multiplexer.

When choosing USB 3 Type-A plug to plug cable(s) you MUST ensure the RX and TX pairs are crossed and VBUS is connected (if RX/TX pairs are not crossed the cable will only work for USB2). Also be aware the multiplexer signals are switched (not repeated/re-driven) so keeping total cable length short between USB host and device (~2M total) is a must for signal integrity.