| ??? 04/05/07 20:47 Read: times |
#136704 - CDC composite device Responding to: ???'s previous message |
This topic from Microchip forum discusses the way to make a composite device for CDC (Communication Device Class).
http://forum.microchip.com/tm.aspx?m...=&\#223235 This method may work to make a multiple virtual COM port support. In this topic, they succeeded to make a composite device using a communication class interface which has entire endpoints (1x interrupt + 2 x bulk) for CDC class. And deleted an usual data class interface. However, this definition doesn't match to the USB CDC spec. The spec expects just an interrupt endpoint in the communication class interface, and bulk endpoints in the data class interface. 3.3.1 Communication Class Interface (usbcdc11.pdf p9) The Communication Class defines a Communication Class interface consisting of a management element and optionally a notification element. The management element configures and controls the device, and consists of endpoint 0. The notification element transports events to the host, and in most cases, consists of a interrupt endpoint. CDC spec from USB.org http://www.usb.org/developer...bcdc11.pdf As this descriptors are out of spec, even if Windows XP would accept it, other OS may reject it. And it is not ensured that Windows support it in future. Tsuneo |
| Topic | Author | Date |
| Multiple USB Virtual COM Ports | 01/01/70 00:00 | |
| CDC composite device | 01/01/70 00:00 | |
| So much for my idea | 01/01/70 00:00 | |
| Union function descriptor | 01/01/70 00:00 | |
| driver development | 01/01/70 00:00 | |
Composite device, again | 01/01/70 00:00 | |
| Virtual COM port vs Direct port | 01/01/70 00:00 | |
| what about real (non-virtual) | 01/01/70 00:00 | |
| And there are lots of serial-to-IP "adapters" | 01/01/70 00:00 |