Table 7-1. Standard Request Availability in Wireless USB Device States (cont.)

7.3.1 Wireless USB Extensions to Standard Requests

This section describes extensions to the standard set of device requests defined in the USB 2.0 specification [1]. This includes extensions to the requests defined in the USB 2.0 specification (Section 9.4) and specific requests defined for Wireless USB. Table 7-2 summarizes the standard Wireless USB device requests and Table 7-20 summarizes the Wireless USB Security Requests.

Table 7-2. Wireless USB-specific Standard Device Requets

The USB 2.0 specification [1], Section 9.4 lists request codes for the standard device commands over the Default Pipe. Table 7-3 is an annotated list of additional standard request codes for devices. The annotations indicate whether the request code is specific to security.

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Table 7-3: Wireless USB Standard Request Codes

The USB 2.0 specification, Section 9.4 lists standard feature selector values for enabling or setting specific features. Table 7-4 is a list of additional standard features selectors for devices. Wireless USB uses one feature selector value (WUSB_DEVICE) then defines a family of Wireless USB specific features which are relative to WUSB_DEVICE feature selector. The commands ClearFeature, SetFeature and GetStatus detail how Wireless USB uses these features.

Table 7-4. Wireless USB Standard Feature Selectors

7.3.1.1Clear Feature

This request is used to clear a specific feature. The USB 2.0 defined uses of this command remain in effect for Wireless USB, see Section 9.4.1 in the USB 2.0 specification. The following description details extensions to this request for Wireless USB.

When the feature selector field (wValue) is set to WUSB_DEVICE, the least significant byte of wIndex is used to further qualify which Wireless USB device feature is to be modified with this request. Wireless USB device features are summarized in Table 7-13. Table 7-5 summarizes which of the Wireless USB features can be modified with the ClearFeature() request.

UnAuthenticated State: If the the specified feature selector is WUSB_DEVICE, device behavior when this request is received while the device is in the UnAuthenticated state is not specified..

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Default State: If the specified feature selector is WUSB_DEVICE, device behavior when this request is received while the device is in the Default state is not specified.

Address State: This request is valid in the Addressed state. Configured State: This request is valid in the Configured state.

Table 7-5. Features Modifiable via ClearFeature()

7.3.1.2Get Status

This request returns status information about different portions of a device. The following description details the extensions to the GetStatus() request for Wireless USB. For a description of the standard USB 2.0 request, refer to Section 9.4.5 in the USB 2.0 specification.

The format of this request is a standard GetStatus() request as defined in USB2.0, with extended definition of the wIndex field when the recipient is DEVICE. The USB 2.0 specification requires that wIndex have a value of zero when bmRequestType specifies the recipient is the device (with a bRequest of GET_STATUS). The extension for Wireless USB encodes wIndex with a value indicating the specific device information the host is interested in. Note that the availability of this request depends on the state of the device and the addressed recipient. For example, a host should not address this request to an endpoint when the device is in the Default state because it has undefined results.

UnAuthenticated State: This request is valid in the UnAuthenticated state.

Table 7-6. Device-Level Status Selector Encodings for wIndex

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Table 7-6. Device-Level Status Selector Encodings for wIndex (cont.)

USB 2.0 Standard Features

When the wIndex value is USB 2.0 Standard Status, the device returns the information illustrated in Figure 7-2.

Figure 7-2. USB 2.0 Standard Status Information Returned by a GetStatus() Request to a Device

Refer to Section 9.4.5 of the USB 2.0 specification for descriptions of the Remote Wake and Self Powered fields. The Self Powered field should always return set to a one (1B) for a Wireless USB device. The default value for Remote Wake is defined in the USB 2.0 specification.

The Battery Powered field indicates whether the device is currently battery-powered. If D2 is reset to zero, the device is powered by a supply that is not a battery. The Battery Powered field value may not be changed by the SetFeature() or ClearFeature() requests.

Wireless USB Features

When the wIndex value is Wireless USB Feature Status, the device returns the information illustrated in Figure 7-3. The default values of these features after any device power-up or reset event is zero.

Figure 7-3. Information Returned by GetStatus(WirelessUSBFeatures)

The TX DRP IE field indicates whether the device is enabled to add a DRP IE to its beacon. If TX DRP IE is a one, the device transmits the DRP IE information set by the cluster host. This field is changed by SetFeature() and ClearFeature(). This is a read-only field unless the device is a Self-beaconing device.

The Transmit Packet field indicates whether the Directed Packet Transmission feature is active. See Section 4.3.7.2.1 for a description of device behavior when doing Directed Packet Transmission.

The Count Packets field is set if the device is enabled for counting packets and reset otherwise. See Section 4.3.7.2.2 for a description of device behavior when enabled for counting packets.

The Capture Packets field is set if the device is enabled for capturing a packet and reset otherwise. See Section 4.3.7.2.3 for a description of device behavior when enabled for capturing a packet.

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Channel Information

When wIndex value is equal to Channel Info, the device must return the information it has gathered with regards to the state of the underlying PHY channel. The format of the data returned is summarized in Table 7-7. A host can use this command to determine how well the device is receiving MMCs from the host.

Table 7-7. Wireless USB Channel Status Information Returned by Device

Received Data

When wIndex value is equal to Received Data, the device must return the information it has gathered from the latest Count Packets or Capture Packet operation. Section 4.3.8.3 describes operation of the Count Packets and Capture Packet operations. The format of the data returned is dependent on which operation was last completed.

Table 7-8 shows the format of data returned from a Count Packets operation. For each counted packet the device returns a 10 byte block that includes the Reception Time, the LQI, and the first six bytes of the MAC header.

Table 7-8. Count Packets Data format

Table 7-9 shows the format of data returned from a Capture Packet operation. For the captured packet, the device returns the MAC header and payload. The device also provides the time the packet was received and indicates if there was any problem receiving the packet.

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Table 7-9. Capture Packet Data format

LQI is an average SNR value at the FFT output for the received packet.

Table 7-10. Definition of LQI values

MAS Availability

When the wIndex value is equal to MAS Availability, the device will then proceed to accumulate information from its neighbor’s beacons about which MAS slots are available for this device to use (not reserved by any neighbor not a member of the Wireless USB cluster). Note that the device may have MAS Availability information that is current so that it does not have to accumulate the information. The data content of the data

returned by the device is formatted as illustrated in Table 7-11. The device must ignore its host’ s DRP IEs for the current Wireless USB channel when building its availability map.

The host must only issue this GetStatus request to a device that has identified itself as a Self-beaconing device. A Nonor Directed Beaconing device must respond to this request with a Request Error.

Table 7-11. MAS Availability Device Status Format

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