Create an artificial "USB Serial" port, possible?

Projects Networking, Protocols, and Devices
1

I've bought a female Micro-USB connector, and I was wondering if there's an easy way to plug the +D and -D into any arduino board (Mega, Uno, Nano, whatever...) and use the Wire, Serial or SPI (or any) libraries to send messages through the port (Hence make it a virtual serial port), like when you plug the builtin USB port to program it.

The idea is to communicate the machine with the PC through a custom software, well in fact I have not a clear idea.
For now I'll just write test programs into Processing I guess.

Cheers!

PD: Sorry if the question is stupid and the answer plain dead simple

2

I think one of the ATTiny AVRs has a software USB implementation in its bootloader. Beyond that I know little else about it. Hopefully somebody else will pitch in and advise.

3

There is already an USB connector on the board; why buy another one? What did you exactly buy? Post a link.

What do you want to achieve? Read SPI/Wire/Serial from some device and send that to a PC?

4

SigmaSoldi3R:
I've bought a female Micro-USB connector, and I was wondering if there's an easy way to plug the +D and -D into any arduino board (Mega, Uno, Nano, whatever...) and use the Wire, Serial or SPI (or any) libraries to send messages through the port (Hence make it a virtual serial port), like when you plug the builtin USB port to program it.

If you are thinking that sending I2C or SPI signals through the data lines of a USB connector will be properly interpreted as normal USB data by the PC then the answer is a very firm NO.

USB works at a much higher frequency (480MHz IIRC). If you want to communicate using USB then you need a microchip that is designed to produce USB signals.

The simplest way to have a USB connection is to get a USB-TTL cable and connect it to a serial port (perhaps using SoftwareSerial) on your Arduino.

...R

5

Have a look for virtual USB or V-USB. Sparkfun have a web page about it being used as part of a boot loader for a Tiny84 here:

https://learn.sparkfun.com/tutorials/how-to-install-an-attiny-bootloader-with-virtual-usb/all

You can use the wire, SPI or serial interfaces on your chip to acquire the data and then maybe, depending on your skill level, implement the V-USB interface on some spare pins.

However, I don't know the processing resources the V-USB implementation takes or whether it uses specific pins or functionality provided by a particular AVR variant.

This is the link to the V-USB page where you can find more details: