Specifications

Remote Control and Receiver-Transceiver Specifications and Requirements

for Windows Media Center in Windows Operating Systems

the envelope are typically in the 200-900 μsec range. About 95% of remote controls use some

sort of modulated protocol. Emulator devices must support this protocol.

Flow Control

When transmitting IR, it is possible that the host will push IR data faster than the device can emit

it. Instead of buffering this data, the device should return a negative acknowledge (NAK)

handshake to indicate that it is not ready for the additional data yet. For more information, see

section 8.5.1 of the USB 2.0 specification.

Bootloaders

Version 2 emulator devices must have a bootloader mode to support wake programming, which

is a requirement of the Windows Logo Program. The bootloader is a second mode of the

emulator device that the host can use to program the wake pattern. This mode is independent of

the main operating mode and is discussed in the Bootloader Implementation section.

Two Methods for Wake Programming

The V2 emulator interface supports two different methods for wake programming. These

methods are not necessarily mutually exclusive, but most hardware manufacturers will choose

one or the other.

Payload-Based Programming

The first option is to program the wake pattern in your device based on payload. If you choose

this method, you would program your device in response to a CMD_BOOT_SETWAKEPATTERN

request. The CMD_BOOT_SETWAKEPATTERN gives your device the Protocol, Payload, and

Address for the Wake key and it expects your firmware to watch for this key based on these

numbers. This requires your firmware to be able to decode both the RC6 and Quatro Pulse

protocols, and it expects this firmware to be parameterized in such a way that it can change its

behavior based on these numbers.

This option allows a simple communication between the host and device, but requires a more

complicated firmware.

Block-Based Programming

The second option is to program the wake pattern in your device based on a block of firmware. If

you choose this method, you would program your device in response to a

CMD_BOOT_WRITEBLOCK request. The CMD_BOOT_WRITEBLOCK request allows the host

to send an arbitrarily-sized block of firmware to your device for each <protocol,payload,address>

combination. This option is less demanding on the firmware that is in your device, but it requires

you to install multiple firmware blocks into the user‘s registry (one block of firmware for each

possible wake pattern).

This option allows for a simpler firmware implementation, but it requires the hardware

manufacturer to install firmware blocks into the user‘s registry.

USB Device Descriptors

USB device descriptors are defined by the USB consortium. For information about definitions and

usages of these descriptors, see the developer section of the USB 2.0 specification at

http://www.usb.org.