Circuits @ Home USB host shield "waiting for device"

I’m trying to use the USB host shield mini version to interface with a USB keyboard. Running the QC sketch that comes with the software, it gets stuck at

Checking USB device communication.

Waiting for device …
Waiting for device …
Waiting for device …

I have the following pins connected thus:

(host shield <-> ATMega328/breadboard)
INT <-> 15(INT1)
GND <-> ground
RESET <-> 3.3v
3.3v <-> 3.3v
SS <-> 16(SS)
MOSI <-> 17(MOSI)
MISO <-> 18(MISO)
SCK <-> 19(SCK)
VBUS <-> 5v

None of the GPIO pins are connected.

I can measure the voltage to VBUS and to the USB port at ~5v, and the mouse I’m using to test lights up.

Do i have a rx/tx line crossed or something?

Here's the schematic with pin numbers as per Arduino Pro Mini -> Also make sure your Atmega is powered from 3.3V otherwise USB Host shield won't be able to detect USB device on the bus.


I am using USB Host Mini V2 Shield with Arduino Uno and facing the waiting for device issue:

Connections are:

Arduino --> Shield




PIN 10 --> MAX_SS

11,12,13 --> SPI PINS.

I've powered UNO with external 9V supply and tried connecting a USB Keyboard.

What could be the problem?

Run the example program board_qc and post the serial console output. board_qc is included with the USB host library.

If you are really using the mini board, it might have been killed by the 5V logic levels from the Uno.

Mini shield The Mini is 3.3V-only device; it is designed to mate with Arduino Pro Mini.

Okay. I got the problem with keyboard thing..

Problem was I was connecting 5V from Arduino Uno to VBUS on the shield which is supplying 5V to all the supply lines and hence MAX was not able to detect the USB Device.

Connected an external 3.3V regulated supply to Vcc of MAX and disconnected 5V from VBUS.

It works okay with keyboard.

Now the problem is, I want to connect a Barcode Scanner to it. Following are the cases I am facing..

------------------------Case 1--------------------------------------


  1. VBUS on shield is floating.

  2. VCC on shield is connected to external 3.3V supply.


When I plug in the Scanner into the shield, Arduino UNO restarts and disconnects from PC, thus I cannot see the serial output.

** This can be a power issue.

------------------------Case 2--------------------------------------


  1. VBUS on shield is connected to 5V from Arduino UNO.

  2. VCC on shield is connected to external 3.3V supply.


When I plug in the Scanner into the shield, Arduino UNO does not restart but MAX does not recognize the device as VCC on MAX goes to 5V due to VBUS.

Now, as I supply 5V to VBUS, shield stops recognizing the USB Device and when I keep VBUS floating, Arduino UNO restarts due to some reason.

****I tried connecting external 9V supply to Arduino UNO already.

The USB host board hardware manual discusses cutting a trace so VBUS can be 5V while MAX VCC is 3.3V. But I still think the Uno is driving 5V into the MAX inputs which may eventually kill the MAX. If the trace is not cut, connecting 5V to VBUS shorts the Uno 5V rail to 3.3V rail which might kill the Uno.

The USB host mini board is not designed to work with 5V logic levels and 5V VCC.

USB bar code readers I have used require VBUS=5V. The only USB device that I have seen work with VBUS=3.3V is a keyboard.

Thanks for your help.

Cut the track between VBUS and VCC on USB Shield, isolated them and connected VBUS to 5V, and VCC to 3.3V from Arduino UNO..

Everything is working fine for now.

The USB host mini board is not designed to work with 5V logic levels and 5V VCC.

Didn't understand the context of 5V logic level here.. Will Arduino UNO working 0n 5V logic levels for SPI and ICSP affect the UHS or is it limited to supply only?

Krushna118099, I am trying to do the same with you with a scanner, but i just cant seem to get the USB Host Shield to respond. and i have ran the Board_qc several time and at the end i get this message all the time…

Reset Complete. Waiting for the First SOF…
USB State machine Reached erroe state
Waiting for device…

now on the modification you did would it be too much if i asked for pictures or a diagram of what you did…

i just got the USB Host Shiels Board and i dont want to make an error and destory it, and would like to use some of guide.

Thanks in Advance