Methods and apparatus for adaptive accessory detection and mode negotiation

Abstract

Methods and apparatus for providing device detection and operational mode negotiation entirely over extant high-speed data bus pins or terminals. In one exemplary embodiment, methods and apparatus are disclosed enabling detection, negotiation and serial/video data transfer over USB 2.0 data interface pins in order to consolidate pin count on the interface and associated connector. Existing USB detection mechanisms are also leveraged to the maximum extent so as to eliminate the need for additional detection protocols. This approach allows for smaller connector and parent device form factor, while still maintaining all of the functional capabilities required for that interface. The breadth of USB-capable devices supported by such an interface is also markedly improved over prior art techniques.

1 . A method of operating a peripheral interface of a media-capable device, the method comprising:
 after connection of an accessory to a connector of the peripheral interface, detecting the presence of a power signal on a power conductor of the connector, the power conductor being associated with a USB data interface;   determining the values of first and second signals on respective first and second conductors of the connector, the first and second conductors being associated with the USB data interface;   based on at least the determining, classifying the accessory as either (i) a power supply accessory, or (ii) a USB host device.   
   
   
       2 . The method of  claim 1 , wherein the connector comprises a multi-pin connector having serial, video, and a high speed serialized bus protocol conductors in addition to the power conductor and first and second conductors. 
   
   
       3 . The method of  claim 1 , wherein the determining the values of signals on first and second conductors associated with the USB data interface comprises evaluating for both SE 0  and SE 1  conditions on the D+/D− conductors of the USB interface. 
   
   
       4 . The method of  claim 3 , wherein the classifying the accessory as either (i) a power supply accessory, or (ii) a USB host device, comprises classifying the accessory as a USB host device when neither the SE 0  or SE 1  conditions are detected. 
   
   
       5 . A method of operating a peripheral interface of a media-capable device, the method comprising:
 after connection of an accessory to a connector of the peripheral interface, detecting the absence of a power signal on a power conductor of the connector, the power conductor being associated with a USB data interface;   determining the value of a signal on a conductor of the connector, the conductor being used for detecting the presence of the accessory;   determining the values of first and second signals on respective first and second data conductors of the connector, the first and second conductors being associated with the USB data interface; and   based on the acts of determining, operating the media-capable device as a USB host device.   
   
   
       6 . A portable user device, the device comprising:
 a processor;   a storage device configured for storage of media data; and   a signal interface in data communication with the processor, the interface comprising:
 a multi-terminal connector having a plurality of terminals including a device detection terminal; 
 a high speed serialized protocol interface in signal communication with the connector; and 
 logic in communication with at least portions of the plurality of terminals and operative to perform device detection using at least the device detection terminal; 
   wherein the signal interface is configured to, responsive to at least the device detection, operate according to a host mode.   
   
   
       7 . The device of  claim 6 , wherein the high speed serialized protocol interface comprises a USB 2.0 interface, and the host mode comprises USB 2.0 Host Mode. 
   
   
       8 . The device of  claim 7 , wherein the signal interface is further configured to operate according to a host mode based at least in part on voltages present on respective ones of USB data pins associated with the USB 2.0 interface. 
   
   
       9 . A method of operating a peripheral interface of a media device responsive to connection of a first peripheral device, the method comprising:
 detecting connection of the first peripheral device via a connector;   sampling a power pin of the connector, the power pin adapted to indicate a first mode, or a plurality of second modes, the plurality of second modes comprising at least a host mode and one or more special modes; and   if the power pin indicates the first mode, adapting the peripheral interface to perform slave functionalities for a first protocol; or   if, the power pin indicates the plurality of second modes, sampling an identifier pin of the connector, the identifier pin adapted to indicate at least one of the plurality of second modes.   
   
   
       10 . The method of  claim 9 , wherein the first mode comprises a host mode, and the method further comprises:
 if the identifier pin indicates the host mode, adapting the peripheral interface to perform host functionalities of the first protocol; or   if the identifier pin indicates the one or more special modes, adapting the peripheral interface to conform to the one or more special modes.   
   
   
       11 . The method of  claim 9 , wherein the connector comprises a multi-function connection having at least a high speed serialized bus protocol interface, and the power pin is associated with the serialized bus protocol interface. 
   
   
       12 . The method of  claim 11 , wherein the high speed serialized bus protocol interface comprises a universal serial bus (USB) interface. 
   
   
       13 . The method of  claim 9 , wherein the detecting connection of the first peripheral device via a connector comprises detecting connection via a detection pin of the connector. 
   
   
       14 . Apparatus for use in interfacing an electronic device to an accessory over a high-speed serialized protocol bus interface, the apparatus comprising:
 a connector having (i) a detection pin, and (ii) a plurality of other pins associated with the high-speed serialized protocol bus interface;   logic in operative communication with the detection pin and the plurality of other pins, the logic adapted to:
 detect the presence of the accessory using at least the detection pin; 
 detect the presence or absence of electrical power over at least one of the plurality of other pins of the bus interface; 
 detect the configuration of the accessory using others of the plurality of other pins of the bus interface; and 
 determine, based on the detection of presence of the accessory, presence or absence of electrical power, and configuration of the accessory, whether or not the electronic device should operate in a host mode when connected to the accessory. 
   
   
   
       15 . The apparatus of  claim 14 , wherein the electronic device comprises a media-capable device, and the high-speed serialized protocol comprises a Universal Serial bus (USB) protocol. 
   
   
       16 . The apparatus of  claim 15 , wherein the apparatus further comprises a second high-speed serialized protocol. 
   
   
       17 . The apparatus of  claim 16 , wherein the second high-speed serialized protocol comprises a FireWire (IEEE Std. 1394) protocol. 
   
   
       18 . The apparatus of  claim 14 , wherein the connector comprises a 30-pin connector. 
   
   
       19 . The apparatus of  claim 14 , wherein:
 the at least one of the plurality of other pins of the bus interface over which the presence or absence of electrical power is detected comprises a power pin of the bus interface; and   the others of the plurality of other pins of the bus interface over which the accessory configuration is detected comprises two (2) data pins of the bus interface.