080505
OPERATIONS MANUAL PPM-GX500
6
BIOS
The PPM-GX500 BIOS provides configuration flexibility, performance and AT-compatibility.
It includes enhancements required for embedded applications like the ability to boot
without a keyboard or video monitor present, and save settings to EEPROM. Configuration
options and instructions are discussed in more detail in the
BIOS Supplemental
later in this
manual.
Saving BIOS Setup
The PPM-GX500 provides two methods for saving BIOS setup data:
Standard battery backed CMOS RAM
and
Nonvolatile EEPROM
The battery is enabled/disabled using
J1
pins 5, 6, 7 and 8. For further details, refer to
the
Battery Backup
section later in this manual.
The EEPROM write/read functionality is enabled/disabled at
J1
, pins 1 and 2. The EEPROM
is disabled by installing a jumper on pins 1 and 2 of
J1
.
Visual
Index
2 4
o o
o o
1 3
J1
1-2 Disables EEPROM BIOS Settings
3 4 not used
Real-Time Clock/Calendar
A real-time clock is used as the AT-compatible clock/calendar. It supports a number of
features including periodic and alarm interrupt capabilities. In addition to the time and
date keeping functions, the system configuration is kept in CMOS RAM contained within
the clock section.
Battery Backup
A 350 mAH battery supplies the PPM-GX500 board with standby power for the real-time
clock and CMOS setup RAM.
A power supervisory circuit contains the voltage sensing circuit and an internal power
switch to route the battery or standby voltage to the circuits selected for backup. The
battery automatically switches ON when the VCC of the systems drops below the battery
voltage and back OFF again when VCC returns to normal.
Visual
Index
ENABLE (default)
5 6, 7-8
DISABLE
5-6, 7 8
Master Battery Enable (J1)
2 4
o o
o o
1 3
J1
1-2 Enables EEPROM BIOS Settings
3 4 not used
