How to support two (dual) USB ports?

[jellis00]

Thanks for that, Gadelhas. I reviewed the CP2102. It looks like it is a it is a bridge between a USB host and UART microcontroller like a PIC 18F2550/4550, in a similar manner to the VFC chips recommended by Darrel Taylor and spcw1234 in their below postings. Do you concur?

I guess a USB host bridge is the way I have to go to get two USB ports supported to meet my requirement. My decision on which chip to use (CP2102 or VNC) then boils down to which is the simpler to program and implement. Since the VNC chips can be provided with a pre-compiled firmware to support different USB interfaces, that is definitely a speedup on my development. However, if you already have code that implements the USB interface between an 18F4550 and CP2102 and are willing to share the code, that would be a rapid development process also.

Are you willing to share your code? I don't need the pincount of an 18F4550, so would probably use 18F2550 as smalleer chips, but the code should be almost identical.

Regards, John

[gadelhas]

Thanks for that, Gadelhas. I reviewed the CP2102. It looks like it is a it is a bridge between a USB host and UART microcontroller like a PIC 18F2550/4550, in a similar manner to the VFC chips recommended by Darrel Taylor and spcw1234 in their below postings. Do you concur?

I guess a USB host bridge is the way I have to go to get two USB ports supported to meet my requirement. My decision on which chip to use (CP2102 or VNC) then boils down to which is the simpler to program and implement. Since the VNC chips can be provided with a pre-compiled firmware to support different USB interfaces, that is definitely a speedup on my development. However, if you already have code that implements the USB interface between an 18F4550 and CP2102 and are willing to share the code, that would be a rapid development process also.

Are you willing to share your code? I don't need the pincount of an 18F4550, so would probably use 18F2550 as smalleer chips, but the code should be almost identical.

Regards, John

Hi John;

Yes the CP2102 is only a Uart/USB Bridge. This type of device should be only used for connection to a PC( Or to a device that handles it, it must have the USB Host capability), for instance, if you have some device that only haves UART, and your PC doesn't have a COM/Serial Port to connect it, you should use a UART/USB Bridge like the CP2102.

If you have a device that is allready USB, for instance a PC mouse, or a USB hard disk, and you want to connect to a PIC, then you must use a device like Darrel posted, the Vinculum. This type of device it haves the capability of USB Host/Slave controller IC.

The temperature device that you posted, it allready haves USB, so if you want to interface it woth a PIC, you must you the IC that Darrel posted.

The device that I did with a PIC/USB and CP2102, was to connect to two PCs simultaneously. I cannot share the code, but if you want i can tell you how to do. It's simple, you use the Uart module connected to the CP2102. Int he firmware PIC side, you just do the Hserout command, or the Serout command to feed the data to the Uart of the PIC and then the CP2102 converts to USB and feeds to the PC.
But like a said before, this is not what you want.

Hope you can understand what i wrote, English is not my native language, i'm Portuguese.

Regards
Gadelhas

[spcw1234]

The VNC2 has 2 USB ports on it, you would make both of them the host ports for the temperature sensors. Connect the VNC2 to a PIC using the UART connection as a USB to UART bridge. The PIC does not need USB on it for what you are trying to do. I was unable to confirm if you can set up both USB ports on the chip as a USB host. If not, then you would need to use two of them, but since there are 2 USB ports built into the chip I would imagine you can. I have no real experience (yet) with this chip, but plan to get one in the near future to play with. Good luck, and keep us posted!

[gadelhas]

Hi... again;

The Vinculum II, has 2 USB Ports Host / SLave Controller, the Vinculum I, i don't know.

You can see it here, first item of the "key Hardware features"
http://www.ftdichip.com/Products/ICs/VNC2.htm