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Topic: Arduino Due and Shields (Read 3624 times) previous topic - next topic

eanisha

Hi,

I am currently switching over from a MEGA2560 to a Due because I realized I needed a more powerful microonctroller for my functions.
I am also using a Keyes USB shield with my project. (http://www.thaieasyelec.com/downloads/EFDV521/Datasheet_Keyes_USBHostShield.pdf)
I have been warned that the Due, unlike the mega operates at 3.3V and am concerned whether my USB shield would work with the Due.
I am only using a mouse for my project. But having read through some websites, one sentence seemed a bit concerning : MAX3421E is 3.3V device and USB is 3.3V bus. Therefore, it is essential to always have 3.3V supplied to the shield during operation. USB-specified VBUS voltage is 5V; since all bus-powered devices are designed to be powered from 5V, some of them won't work reliably or even at all from 3.3V. This is especially true for low-speed devices, like keyboards and mice  (https://www.circuitsathome.com/usb-host-shield-hardware-manual/)

I noticed the Due has a 5V pin and am confused as to what its functionality is? Does it serve the same purpose as the 5v pin on a mega? to supply regulated 5v ?

will I need to make hardware modifications to my shield or need to consider alternative power options?
Any help is greatly appreciated.

Many thanks!
Elizabeth

ard_newbie

#1
Feb 16, 2017, 03:51 pm Last Edit: Feb 16, 2017, 03:53 pm by ard_newbie
From   : https://www.arduino.cc/en/Main/arduinoBoardDue

5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

From :  https://www.sparkfun.com/products/11589
DC Current for 5V Pin: 800 mA


From Sam3x datasheet (USB On The Go):

39.2 Embedded Characteristics

 Compatible with the USB 2.0 specification
 Supports High (480Mbps), Full (12Mbps) and Low (1.5Mbps) speed communication and On-The-Go
 10 pipes/endpoints
 4096 bytes of Embedded Dual-Port RAM (DPRAM) for Pipes/Endpoints
 Up to 3 memory banks per Pipe/Endpoint (Not for Control Pipe/Endpoint)
 Flexible Pipe/Endpoint configuration and management with dedicated DMA channels
 On-Chip UTMI transceiver including Pull-Ups/Pull-downs
 On-Chip OTG pad including VBUS analog comparator

eanisha

I cant seem to understand this schematic for the USB shield
i am using : http://www.thaieasyelec.com/downloads/EFDV521/Datasheet_Keyes_USBHostShield.pdf
but i see that there is a 5 v output, but also mentioned compatibility with 3.3 V boards
I'm scared I'll damage my new board. Can you help advice me i its okay for me to try it with the Due board?

ard_newbie

#3
Feb 22, 2017, 04:11 pm Last Edit: Feb 25, 2017, 04:39 pm by ard_newbie

I am only using a mouse for my project....
If you only need a mouse controller, I guess you don't need a shield. The DUE embeddes an USB 2.0, and, e.g. this Library :

USBHOST
will give you a mouse controller.


EDIT : In Arduino playground https://www.arduino.cc/en/Tutorial/MouseController

eanisha

Hi
Thanks so much. Didnt know of this
Does this mean I would need to find a mouse that connects to a micro USB port?
then insert it into the native port on the Due?

Whandall

You probably need an usb otg cable/adapter and the host/otg functionality on the Due.
Ah, this is obviously some strange usage of the word 'safe' that I wasn't previously aware of. (D.Adams)

eanisha


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