Cypress CY4672 manual Enhanced KISSBind

WirelessUSB™ Protocol 2.2

2.2.5Enhanced KISSBind™

KISSBind provides the ability to automatically bind out of the box without any intervention by the user other than installing the batteries. KISSBind essentially is a bind process while in the data mode. The bridge goes through the normal process of pinging and then going to the data mode. The device upon powering up and determining that it is not bound, transmits KISS_BIND_REQ packets on all channels and PN codes looking for a bridge that has not been bound to that specific device. The bridge keeps track of which device is connected and only responds with a KISS_BIND_RESP packet if it is not already bound to that specific device. Once bound, the bridge stores the device specific state in Flash.

HID

When the HID first powers up it checks the validity of the flash bind parameters. If the bind parame- ters checksum is not valid then the HID is considered to be un-bound. The HID then transmits KISS- Bind request packets on all channels and PN codes using a CRC seed of zero in order to locate the bridge. If an AutoACK is received the HID enters the receive state to listen for a KISSBind response packet from the bridge. The HID completes the KISSBind process if a KISSBind response packet is received from the bridge. If, after RX_PACKET_TIMEOUT (ms), the HID does not receive from the bridge it then resumes the channel/PN code search for the bridge. If the search sequence is unsuc- cessful after BIND_RETRY_COUNT attempts, then the HID enters a low power state waiting for a button press or other activity and begin the search process all over.

Bridge

The bridge, upon powering up, enters the ping mode in order to locate a suitable channel/PN code based on its MID. When the ping mode is complete the bridge then enters the data mode. If a KISS- Bind Request packet is received, the bridge checks the bind status for the specific device that sent the KISSBind request (mouse or keyboard) based on the device type in the packet header. If the specific device has not been bound then the bridge proceeds by sending a KISSBind response packet and completing the KISSBind process. Once an AutoACK is received from the HID in response to the KISSBind response, the bridge updates the Flash bind status for the specific device.

18 CY4672 Reference Design Guide, Document # 001-16968 Revision **

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