Hi, On Wed, Jul 02, 2008 at 07:45:25AM -0400, Gregg C Levine wrote: > A USB cable configured to connect two systems together, such as a > laptop to receive files from a desktop is simply two USB-A cables > wired to an appropriate logic array. This would (Or "should be". > Either way) probably be the latest generation in USB Gadget > hardware.
Yes. But the logic "array" is quite complex, and implements several layers of protocol. Please look at chapters 5, 8 and 9 in the USB specification for a description of the protocol. > Ideally a Linux system can use this to talk to an appropriately > configured system, provided the target was built using the debug > features turned on for the USB stack layer. Not enough. These are the hardware requirements: * The target USB controller must be EHCI * The target USB controller must implement the optional Debug Port * The target board must have a USB connector for the physical port that supports Debug Port. It is always only one particular port. * The "cable" must implement the Debug Device functional specification. See links on http://coreboot.org/EHCI_Debug_Port > While I have here hardware for trying out this idea, namely my > Linux development station, I have not as yet chosen a target. You will also need the debug device. I suggest ordering the NET20DC product from semiconductorstore.com. //Peter -- coreboot mailing list [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
