Page 58 - PDA Robotics Using Your Personal Digital Assistant to Control Your Robot

PDA 04 5/27/03 8:27 AM Page 34
PDA Robotics
Characteristics of IrDA Control Physical Signaling:
• Distance and range equivalent current unidirectional IR remote
control units (minimum 5 m range).
• Bidirectional communication is the basis of all specs.
• Data transmission at 75 kb/s at the top end.

• The data are coded using a 16-pulse sequence multiplied by a
1.5-MHz subcarrier, which is allocated for high-speed remote
control in IEC 1603-1, although this base band scheme has har-
monics that can intrude upon other IEC bands.
• Data packets are protected with a CRC (CRC-8 for short packets
and CRC-16 for long packets). The physical layer is optimized
for low-power usage and can be implemented with low-cost
hardware.

Characteristics of IrDA Control MAC:

• Enables a host device to communicate with multiple peripheral
devices (1:n) and up to eight peripherals simultaneously.
• Ensures fast response time (13.8 ms basic polling rate) and low
latency.
Asymmetric MAC provides for dynamic assignment and reuse of
peripheral addresses. Scheduling of media access is actually buried in
the HID LLC.

Characteristics of the IrDA Control LLC:
• Provides reliability features that provide data sequencing and
retransmission when errors are detected.
• Works with an HID-IrDA control bridge to enable the link control
functions of USB-HID.
• All required and optional layers of the IrDA Data and IrDA
Control specifications are described in specifications that can be
downloaded at no charge from the IrDA Web site: www.irda.org.
Interop product registration is strongly advised on this site.

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