UUGear Zero4U User manual

Copyright © 2017 UUGear s.r.o. All rights reserved.
Zero4U
4-Port USB Hub for Raspberry Pi Zero
User Manual (revision 1.20)

Copyright © 2017 UUGear s.r.o. All rights reserved.
Table of Content
Product Overview ................................................................................................. 1!
Package Content .................................................................................................. 3!
Specifications ....................................................................................................... 4!
About Powering Mode .......................................................................................... 5!
Self-Power Mode .......................................................................................... 5!
Bus-Power Mode .......................................................................................... 5!
Usage Guide ........................................................................................................ 6!
Troubleshooting: USB Hub Not Recognized ........................................................ 9!
Revision History ................................................................................................. 11!

1
Product Overview
Zero4U is a 4-Port USB hub designed for Raspberry Pi Zero. It extends the only data
micro USB port on Raspberry Pi Zero and gives you 4 standard USB ports, which
allows you to connect more USB devices to your Raspberry Pi Zero.
The board size of this USB hub is exactly the same with Raspberry Pi Zero, and can
be firmly attached under Raspberry Pi Zero back-to-back. There are 4 pogo pins on
the USB hub board and they will attach the +5V, GND, USB D+ and USB D- testing
pad at the back of Raspberry Pi Zero, so you don’t either need soldering wires, or the
USB-OTG cable and USB – mini USB cable to connect the USB hub and Raspberry
Pi Zero.
Although it is designed for Raspberry Pi Zero, you can still use it as a normal USB hub
for other models of Raspberry Pi, or any computer that has USB port.
There are two versions of Zero4U, one is for Raspberry Pi Zero V1.2 (without camera
connector) and the other is for Raspberry Pi Zero V1.3 (with camera connector). They
have the same functionality but the location of pogo pins are slightly different.
Also there are two revisions for V1.3. The second revision uses more surface
mounted components (the crystal and the XH2.54 connector).
The figures below show how they look like:

2
Reversion 1 (for V1.2 and V1.3)
Reversion 2 (for V1.3 only)
1~4) Downstream USB ports
5~8) White LEDs as activity indicators
9) Two pogo pins at back for data connection
10) Alternative DC 5V power in
11) Two pogo pins at back for power connection
12) Blue LED as power indicator
13) Upstream mini USB port

3
Package Content
Each package of this USB hub contains:
l 4-port USB hub board x 1
l Plastic spacer x 4
l M2.5 x 10mm screws x 4
l M2.5 nuts x 4
l Ferrite Ring x 1 (for V1.3 only)

4
Specifications
Dimension:
65mm x 30mm x 9mm
Weight
14g (net weight without any accessory)
Standards
USB Specification Revision 2.0 and 1.1 compatibility
Single Transaction Translator (STT)
Data Speed
USB v1.1: 12 Mbps
USB v2.0: 480 Mbps
USB Ports
Upstream: 1 (mini-USB or via pogo pins)
Downstream: 4
LED Indicators
Power: 1 (blue)
Port Activity: 4 (white)
Power Mode
On Raspberry Pi Zero: Self-Power
On Other Models: Bus-Power or Self-Power
Output Voltage
DC 5V
Output Current
Bus-Power: maximum 500mA for all ports
Self-Power: maximum 2A for all ports
Static Current
~1mA
Operating Temperature
0℃~70℃
Storage Temperature
-20℃~80℃
Humidity
0~80%RH, no condensing
Remarks: when using Zero4U with Raspberry Pi Zero, Ethernet gadget should
be disabled, or the USB hub could not be recognized.

5
About Powering Mode
A USB hub could be powered by the USB bus (bus-power mode), or be powered by
the power supply (self-power mode). Bus-power mode is simpler as it does not need
to have external power supply, but it has quite limited ability to power the devices on
the USB hub. When you are trying to power more devices with higher current, it is
recommended to use the self-power mode.
This USB hub supports both bus-power mode and self-power mode.
Self-Power Mode
This USB hub in self-power mode can output up to 2,000mA current for all USB ports.
When you attach this USB hub to Raspberry Pi Zero, it will take power from the Zero
and work in self-power mode.
If you use a USB - mini USB cable to connect this USB hub to other models of
Raspberry Pi, and you connect power supply to the USB hub (via the white JST
XH2.54 2-pin connector on board), then it is still working in self-power mode. For
Raspberry Pi A, B or A+, it will also back-power the Raspberry Pi, unless you remove
the resistor R8 on board.
Bus-Power Mode
This USB hub in bus-power mode can output up to 500mA current for all USB ports. If
you are using the first revision of Raspberry Pi A/B, the maximum output current for all
USB ports is only about 100mA, because the USB port on Raspberry Pi (first revision)
has a 140mA polyfuse.
If you use a USB - mini USB cable to connect this USB hub to other models of
Raspberry Pi, and you don’t connect power supply to the USB hub, then it is will work
in bus-power mode, and it will draw power from the USB bus.

6
Usage Guide
To att ac h th is U SB h ub to Ra sp be rry P i Zer o, s i mp ly p ut the m ba ck -to-back together
and place the plastic standoff between them, then use the plastic screws and nuts to
firmly fix the 4 corners.
Please make sure to attach in the correct direction, so the 4 pogo pins on the USB
hub can accurately contact to the PP1, PP6, PP22 and PP23 testing pads on the back
of Raspberry Pi Zero.
Now you can connect power supply to Raspberry Pi Zero, either micro USB port will
do, then you will see both Raspberry Pi Zero and the USB hub are powered. If you
plug a USB device into any of the 4 USB ports, the port activity LED (white) will light
up.
If you want to use Zero4U on Raspberry Pi Zero W, only the Zero4U for V1.3 has the
possibility, as the positions for PP1, PP6, PP22 and PP23 testing pads are the same
for Raspberry Pi Zero V1.3 and Raspberry Pi W. You will also need to use the ferrite
ring (included in the package) to protect the pogo pins from WiFi interference. More
details about the interference from on-board antenna could be found here.

7
The picture below shows how to mount Zero4U on Raspberry Pi Zero W, with the
ferrite ring between them.
Remarks: this USB hub has only one transaction translator (TT) for all downstream
USB ports. Please try not to connect any USB 1.1 device to the USB hub; otherwise
all devices on the hub will be slowed down to the USB 1.1 speed (12 Mbps). If you
only connect USB 2.0 devices to this USB hub, all of devices on the hub can work with
USB 2.0 high speed (480 Mbps), if they support USB 2.0 standard.
If you want to connect this USB hub to other Raspberry Pi models, you will need a
USB - mini USB cable (not included in the package).

8
In the picture, the power supply is connected to Raspberry Pi, and the USB hub is
powered by the USB bus. This will limit the output current to 500mA for all USB ports
on the hub.
If you also connect an alternative power supply to the USB hub (via the white
connector on board), the USB hub will work in self-power mode and it can output up to
2A current for USB ports.