102
CY4636 WirelessUSB™ LP Keyboard Mouse Reference Design Kit User Guide, Doc. # 001-70355 Rev. *A
has elapsed while in Bind Mode without receiving a Bind Response, the HID exits Bind Mode and
restores the Channel and PN Code settings that were in use prior to entering Bind Mode. Bind Mode
should last long enough for the user to locate and push the button on both the bridge and the HID. A
user-initiated event can cause the HID to enter Bind Mode from any other mode.
[*The timeout value is configurable using the BIND_RETRY_COUNT define.]
Bridge.
Upon entering Bind Mode the bridge sets the current channel and PN code to the channel
and PN code specified in the Bind ID. The bridge listens for a Bind Request on each channel for
approximately 320 ms before selecting the next channel using the Channel Selection Algorithm. This
reduces the possibility of the bridge not receiving the Bind Request from the HID in the event of
channel interference. If the bridge receives a Bind Request from the HID containing a supported
device type, it sends a Bind Response containing the bridge's Manufacturing ID and then switches to
Ping Mode. The bridge also switches to Ping Mode if the defined* time period has elapsed while in
Bind Mode. The Channel Selection Algorithm uses the Bind ID to produce the channel subset for
Bind Mode.
[*The timeout value is configurable using the NUM_CHANNELS_PER_SUBSET define.]
A.3.8.5
Data Mode
HID.
When the HID application has data to send to the bridge the HID transmits a DATA packet and
listens for an AutoACK. If an AutoACK is not received, the HID retransmits the packet. If the HID
does not receive an AutoACK after a defined number of retransmissions of the DATA packet it
assumes the channel has become unavailable due to excessive interference and moves to Recon-
nect Mode.
Bridge.
Connected Mode allows application data to be transmitted from the HID to the bridge. The
bridge should continuously listen for DATA packets from the HID. When valid data is received from
the HID the bridge sends an ACK to the HID and sends the data to the USB host. If invalid data is
received the bridge ignores the packet and listens for the HID to retransmit the data. The bridge
monitors the interference level and moves to Ping Mode if the defined* interference threshold is
reached. This ensures that the bridge is operating on a clean channel.
[*The interference threshold value is configurable using the RSSI_NOISE_THRESHOLD define]
A.3.9
Packet Structures
The first byte of each packet is the Header byte. Some packets may consist only of the header byte
while other packets may contain up to 5 bytes.
Type[7:4]: The following packet types are supported:
BIND_REQ (HID) = 0x 0, // Bind Request Packet Type
BIND_RESP(bridge)= 0x0, // Bind Response Packet Type
CONNECT_REQ = 0x1, // Connect Request Packet Type
CONNECT_RESP= 0x 2, // Connect Response Packet Type
PING_PACKET = 0x 3, // Ping Packet Type
DATA_PACKET = 0x 4, // Data Packet Type
Byte
1
Bits:
7:4
3:0
Field:
Packet Type
Res
