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Chapter 8

 

Wire Adapter

Wireless Universal Serial Bus Specification, Revision 1.0

8.5.5.2 HWA Isochronous IN Responsibilities

The HWA is required to process received wireless isochronous data packets and return the information over the wired interface using the transfer result and HWA isochronous packet status format. The HWA parses the Wireless USB isochronous packet header information and places the data only in the data buffer that will be returned to the host software.

The HWA must start performing IN transaction to the downstream Wireless USB endpoint as soon as possible after receiving the Isochronous Transfer request. The first Wireless USB packet is placed in the first location in the RPipe buffer. The presentation time in this Wireless USB Packet along with the wPresentationTime in the subsequent Wireless USB packets and the bInterval in the RPipe descriptor is used to determine the location in the RPipe buffer for the data in those Wireless USB packets. The HWA must update the Packet Status length information for each Wireless USB packet received based on the segment length information present in the Wireless USB Isochronous header. For a complete transfer, the dwNumOfPackets field in the Isochronous Transfer request must be equal to the total number of segments in the Wireless USB packets received from the Wireless USB endpoint.

Once the HWA has received all the data from the Wireless USB endpoint or the Wireless USB channel time exceeds the wPresentationTime specified in the Isochronous Transfer request, it must retire the Isochronous Transfer request and send a Transfer Result along with the Packet Status information back to the host on the Data Transfer Read endpoint.

8.5.5.3 HWA Isochronous Transfer Completion

The data and result of an isochronous transfer to a Wireless USB device connected downstream of a Host Wire Adapter are returned to host software on the Data transfer read endpoint. On completion of an Isochronous transfer on an HWA, the HWA will send a transfer completion notification on its notification endpoint and transfer result will be available to host software on its Data Transfer Read endpoint. The Transfer Result will contain the number of Packet Status records to be expected immediately after the Transfer Result. The format of the Isochronous Packet Status is shown in Table 8-59. If this was an IN transfer request, then the data read from the device will be sent after the packet status information.

Table 8-59. HWA Isochronous Packet Status

Offset

Field

Size

Value

 

Description

 

 

 

 

 

0

wLength

2

Number

Length of this block of data

 

 

 

 

 

1

bPacketType

1

A1H

ISO_PACKET_STATUS_TYPE

 

 

 

 

 

2

bReserved

1

Zero

Reserved for future use, must be zero.

 

 

 

 

 

4

PacketStatus[n]

Variable

Array

This is an array of Packet Length and Packet Status

 

 

 

 

tuples.

 

 

 

 

 

wPacketLength

Actual length of data sent or

 

 

 

 

 

received in the frame

 

 

 

 

wPacketStatus

Status of this Packet

8.6Radio Control Interface

An HWA must expose a Radio Control interface so that host software can control the radio. This section describes the Radio Control interface required to control the UWB Radio. This interface consists of one interrupt endpoint. This endpoint along with the default control endpoint of the device is used to control the UWB Radio in the Device.

Control Endpoint

This is the default USB control endpoint. All radio control commands

 

are sent to the device through this endpoint.

Radio Control

This Interrupt IN endpoint is used to return status and results of the

Interrupt Endpoint

radio control commands sent on the default control endpoint.

 

Asynchronous UWB Radio notifications are also sent back to the host

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Соседние файлы в папке Wireless USB Specification Revision 1.0 May 12, 2005