PORTS Forum

Ports and Interfaces => USB => Topic started by: jbrady on July 08, 2010, 01:37:33 pm

Title: USB On-The-Go ?
Post by: jbrady on July 08, 2010, 01:37:33 pm

Hi ------
I have a board that I designed a couple of years ago using an FTDI chip FT245RL working fine, but now I am looking at re-spinning it where I want the board to still act as a USB slave to a PC, but now also allows me to plug in a USB memory stick and read / write it.  I gather I am talking about USB on the go here ?  Wonder if anyone has suggestions, like are there any FTDI chips that can do this? ... Want to have a single USB port, but am I better off with 2 seperate ports?  Am also wondering if I will need to somehow integrate a complex USB stack into my CPU firmware to handle the memory stick ... am not currently using any O/S.
Thanks,
Jim

Title: Re: USB On-The-Go ?
Post by: Jan Axelson on July 08, 2010, 02:03:55 pm

OTG is for products that can function as both host and device but not both at the same time. The other option is an embedded host, which functions as a limited-capability host and may also contain a USB device controller and function as a device.

FTDI's Vinculum and GHI Electronics' USBwiz handle the USB protocols for flash drives and other devices.
 
My OTG and Embedded Hosts page has links to info:

http://www.janaxelson.com/embedded_host.htm

Jan