Ampro Corporation Single Board Computer 700 - Manual (Page 56)

Chapter 3 Hardware
50 Reference Manual ReadyBoard 700
Infrared (IrDA) Port (J17)
The Infrared Data Association (IrDA) control provides 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. This header can be enabled/disabled and configured for HPSIR or ASKIR signals in BIOS
Setup. Refer to Chapter 4, BIOS Setup for more information.
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 19.2k
baud. Each word is sent serially beginning with a zero value start bit. A zero is sent when a 500kHz
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 Southbridge and
Super I/O controller chip (VT82C686B) specifications available from the manufacture’s web site and
referenced earlier in this manual. For more information, refer to the VIA VT82C686B chip databook
and the Infrared Data Association web site at
http://www.irda.org .
NOTE For faster speeds and infrared applications not covered in this brief description,
refer to the VT82C686B chip specifications by VIA Technologies, Inc.
Table 3-25. Infrared Interface Pin/Signal Descriptions (J17)
Pin # Signal Description
1 +5V +5V
2 IRTX IR Transmit Data
3 IRSel IR Mode Select
4 IRRX IR Receive Data
5 GND Ground
Notes: The shaded area denotes power or ground.
Real Time Clock (RTC)
The ReadyBoard 700 contains a Real Time Clock (RTC) and along with the CMOS RAM are backed up
with a Lithium Battery attached to the ReadyBoard. If the battery is not present or has failed, the BIOS
has a battery-free boot option to complete the boot process.
Oops! Jumper (BIOS Recovery)
The Oops! jumper is provided in the event the BIOS settings you’ve selected prevent you from booting
the system, but does not change the Time & Date in the BIOS. Refer to the CMOS Normal/Clear
jumper (JP3) to reset the BIOS to Jan 1, 1980; 00:00.
By using the Oops! jumper you can prevent the current BIOS settings in Flash memory from being
loaded, forcing the use of the default settings. Connect the DTR pin to the RI pin on Serial port 1 (COM
1) prior to boot up to prevent the present BIOS settings from loading. After booting with the Oops!
jumper in place, remove the Oops! jumper and go into BIOS Setup. Change the desired BIOS settings,
or select the default settings, and save changes before rebooting the system.
To convert the Serial 1 interface to an Oops! jumper, short together the DTR (4) and RI (9) pins on the
Serial Port 1 DB9 connector as shown in Figure 3-2.