Serial-USB-USB-Serial communication

[Mithun_K_Das]

We use CH340 for serial to USB communication. If we use the same two sets, like the image below:

Is it possible to make communicate with two devices that have serial/UART options, we use CH340 for Serial/USB conversion, and again USB/serial conversion is done with another CH340 which gives a serial output for the next device.

*** I have no experience with USB communication. Just let me know if it is possible or not.

 

[KlausST]

Hi,

USB needs an USB_HOST to operate.. and to communicate with slaves.
The HOST controls timing, power supply, manages the slaves .. and all other stuff that needs to be done.

On a quick view into the datasheet I don´t think CH340 can act as a USB_HOST.
USB_HOSTs usually are PCs, Laptops, Tablet, Raspberry..

I´ve never seen a stand alone USB_HOST device. (But maybe such thing exists)

***
But generally I ask myself why you want to do this. USB is a quite flexible interface for all kind of data and end devices.
So why using such a complex hardware and protocol for simple UART-style communication?

USB isn´t an interface for long distance... so what benefit do you see in a UART-USB-USB-UART communcation?

Klaus

 

[Mithun_K_Das]

USB needs an USB_HOST to operate.. and to communicate with slaves.
The HOST controls timing, power supply, manages the slaves .. and all other stuff that needs to be done.

On a quick view into the datasheet I don´t think CH340 can act as a USB_HOST.
USB_HOSTs usually are PCs, Laptops, Tablet, Raspberry..

I´ve never seen a stand alone USB_HOST device. (But maybe such thing exists)

ok, understood.

But generally I ask myself why you want to do this. USB is a quite flexible interface for all kind of data and end devices.
So why using such a complex hardware and protocol for simple UART-style communication?

USB isn´t an interface for long distance... so what benefit do you see in a UART-USB-USB-UART communcation?

I have a battery pack, that is using CH340 to communicate through the USB port. It takes command and changes voltage, output, etc. To make any change, each time I need to connect it with a PC. But this pack is supplying power to a microcontroller board in which I have UART. That is why, if it was possible to make something that can communicate with the battery pack through USB while I give the command through UART, the whole work would be easy for me.

That is why I'm looking for something that can help. But not willing to use Raspberry Pi, because that will bring more complexity as well as cost.

 

[KlausST]

Hi,

OK, I understand.

USB_slave to USB_slave won´t work.

What you can do:
* Check whether USB_OTG is possible
* use a USB_HOST (FTDI Vinculum for example)
* or modify the slave and use just the UART signals (using jumper, switch...)

Klaus

 

[Mithun_K_Das]

That means, If there is a USB host in a microcontroller, we can use that?

 

[KlausST]

Hi,

That means, If there is a USB host in a microcontroller, we can use that?

and the hardware, and the power supply and the protocol stack ... yes

Klaus