Chapter 3
Hardware
ReadyBoard 620
Reference Manual
29
Infrared (IrDA) Port
The Infrared Data Association (IrDA) signals pass through a two-way communications header for an
external IrDA device using infrared as the transmission medium. There are two basic infrared
implementations provided; the Hewlett-Packard Serial Infrared (HPSIR) and the Amplitude Shift Keyed
Infrared (ASKIR) methods. HPSIR is a serial implementation of infrared developed by Hewlett-Packard.
The IrDA (HPSIR and ASKIR) signals share the same header as the IrDA model select signals. These
signals are operating system (OS) and/or application dependent and are based on the user’s application, but
can be configured and enabled in the BIOS Setup Utility.
The HPSIR method allows serial communication at baud rates up to 115k baud. Each word is sent serially
beginning with a zero value start bit. A zero is sent when a single infrared pulse is sent at the beginning of
the serial bit time. A one is sent when no infrared pulse is sent during the bit time.
The Amplitude Shift Keyed infrared (ASKIR) allows serial communication at baud rates up to 19.2 k baud.
Each word is sent serially beginning with a zero value start bit. A zero is sent when a 500 kHz waveform is
sent for the duration of the serial bit time. A one is sent when no transmission is sent during the serial bit
time.
Both of these methods require an understanding of the timing diagrams provided in the Super I/O controller
(W83627HF) specifications available from the manufacture’s web site and referenced earlier in this manual.
For more information, refer to the Winbond W83627HF specifications and the Infrared Data Association
web site at
http://www.irda.org
.
Note:
The shaded areas denote power or ground.
System Management Bus (SMBus)
The I/O Hub (Southbridge) chip (CS5536) contains both a host and slave SMBus port; but the host cannot
access the slave internally. The slave port allows an external master access to the I/O Hub through connector
(J20). The master contained in the I/O Hub is used to communicate with the SODIMM EPROM, Super I/O,
Ethernet 1 and 2, and the clock generator.
lists the device name and corresponding reserved
binary addresses on the SMBus.
9
GPIO2
User defined
10
GPIO3
User defined
NOTE
For faster speeds and infrared applications not covered in this brief description, refer
to the W83627HF chip specifications by Winbond Electronics Corp.
Table 3-12. Infrared Interface Pin/Signal Descriptions (J21)
Pin #
Signal
Description
1
VCC
+5 Volts DC +/ 5%
2
IRTX
IR Transmit Data
3
CIRRX
IR Mode Select
4
IRRX
IR Receive Data
5
GND
Ground
Table 3-13. SMBus Reserved Addresses
Component
Address Binary
SODIMM EPROM
1010,000x
b
Clock Generator
1101,001x
b
Table 3-11. User GPIO Signals Pin/Signal Descriptions (J4) (Continued)
Содержание ReadyBoard 620
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