User manual

Kontron Compact Computers AG SMX945 Detailed Manual V1.1

3.1.2. Battery Backed Clock (RTC)

An AT compatible date/time clock is located within the chipset. The device also contains a CMOS static

RAM, compatible with that in standard ATs. System configuration data is normally stored in the clock chip's

CMOS RAM in a manner consistent with the convention used in other AT compatible computers.

Connect an external Lithium battery of 3.0V-3.6V to the RTC pin.

The battery-backed clock can be set by using the Kontron Compact Computers SETUP at boot-time.

Addresses: 70h = Index register

71h = Data transfer register

RTC-Address MAP: 00-0F Real time clock

10-3F BIOS setup (Standard)

40-7F Extended BIOS

Voltage range: 2.0-3.6V DC

With an external Lithium 3.6V / 400mAh battery, the board will work for over 10 years without needing a

replacement battery. The chipset consumes the following currents:

Typical battery current at 25°C: 2.4uA @ typ. 3V DC

3.1.3. Watchdog

The watchdog timer detects a system crash and performs a hardware reset. After power up, the watchdog is

always disabled as the BIOS does not send strobes to the watchdog. In case that the user wants to take

advantage of the watchdog, the application must produce a strobe at least every 800 ms. If no strobe occurs

within the 800 ms, the watchdog resets the system.

For more information, please refer to the driver/software/BIOS manual SMX945_BIOS on the Product CD.

The watchdog feature is integrated in the INT15 function.

There are some programming examples available:

Product CD-Rom or customer download area: \tools\SMX945\int15dl\...

3.2. Watchdog Control

Interface/Function On the smartModule Circuits needed on the OEM board

External WatchDOG Control Standard – automatically

strobed with 32kHz