I have the MBC1760 eval-board for soft development and working on a new PCB. Suppose, I have both A(host) and B(device) connectors. Their VBUS and GND are handled separately. And I have another GPIO pin that selects which connector will be active. When I select HostMode, the D+,D- will be pulled-down. When I select DeviceMode, the D+ will be pulled-up. So I will be able to activate one of the connectors from the program menu, in theory. Has anybody done such a setup ? What problems may I see ? Any suggestions ? Thanks In Advance...
> Suppose, I have both A(host) and B(device) connectors. Their VBUS and GND are handled separately. When I select HostMode, the D+,D- will be pulled-down. When I select DeviceMode, the D+ will be pulled-up. So I will be able to activate one of the connectors from the program menu, in theory.
You have to switch the D+/D- lines with analog switches. Without these switches, an external self-powered device connected to the A connector conflicts with your device, when your device connects to a PC over the B connector.
For full/low speed, these variations of analog switches are available.
Analog Devices - Switching in USB Consumer Applications www.analog.com/.../usb_switch.html
ON semiconductor www.onsemi.com/.../parametrics.do
Fairchild www.fairchildsemi.com/.../USBGuide_ENG_pgs.pdf
Maxim MAX4906 www.maxim-ic.com/.../3020
etc.
Tsuneo