ADLINK Technology LittleBoard 735, Reference Manual

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Chapter 3 Hardware
LittleBoard 735 Reference Manual 37
SMBus Interface
Table 3-21 lists the pin signals for the J45 SMBus Reset header, which uses 5 pins, single row, and 0.49"
pitch.
Note: The shaded areas denote power or ground.
Oops! Jumper (BIOS Recovery)
The Oops! jumper is provided in the event the BIOS settings you have selected prevent you from booting the
system. By using the Oops! jumper you can prevent the current BIOS settings in the EEPROM 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 A interface to an Oops! jumper, short together the DTR (7) and RI (8) pins on Serial A
(J11) header for Serial Port 1. As an alternate, short the equivalent pins, 4 and 9, on the Serial Port 1 DB9
connector as shown in Figure 3-2 .
Figure 3-2. Oops! Jumper Connection
Serial Console
The LittleBoard 735 supports the serial console (or console redirection) feature. This I/O function is
provided by an ANSI-compatible serial terminal, or the equivalent terminal emulation software running on
another system. This can be very useful when setting up the BIOS on a production line for systems that are
not connected to a keyboard and display.
Serial Console Setup
The serial console feature is implemented by connecting a standard null modem cable or modified serial
cable (or “Hot Cable”) between one of the serial ports, such as Serial 1 (J11A) and the serial terminal, or a
PC with communications software. The BIOS Setup Utility controls the serial console settings on the
LittleBoard 735. Refer to Chapter 4, BIOS Setup for the settings of the serial console option, the serial
terminal, or PC with communications software and the connection procedure.
Table 3-21. SMBus Pin/Signal Descriptions (J45)
Pin # Signal Description
1 SCL SMBus Clock Reset
2 GND Ground
3 SDA SMBus Data Reset
4 VCC +3.3 Volts DC +/ 5%
5 ALERT SMBus Alert
Serial A Interface (J11)
for Serial Port 1
(or COM1 Port)
1
2
3
4
5
6
7
8
9
10 20
19
Top View
5 4 3 2 1
9 8 7 6
Standard DB9 Serial
Port Connector (Male)
Front View
Or
LB735Oopsjumper