I'm trying to use the circuitsathome.com 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 ...
Here's the schematic with pin numbers as per Arduino Pro Mini -> https://www.circuitsathome.com/chome_downloads/UHS_mini_10.pdf 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.
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..
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.
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.
gdsports:
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.