User guide

User Guide CC3-CAJUN • Low Power CompactPCI CPU
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EKF Elektronik GmbH • Philipp-Reis-Str. 4 • 59065 Hamm • Germany
Tel. [phone] • Fax. [phone] • [e-mail] • www.ekf.com
Watchdog/Reset
The CC3-CAJUN is provided with two MAX6705 supervisor circuits, which monitor the supply
voltages 3.3V and 5V, and generate a power-on reset signal. The manual push-button reset is
also passed through the MAX6705s for appropriate pulse conditioning.
The reset push-button (if present) is situated at the front panel. The button is indent mounted
behind the front and requires a tool, e.g. pen to be pressed, preventing from being inadvertently
activated. Due to front panel space limitations, those versions of the CC3-CAJUN with a DVI
video connector do not provide a reset push-button, but have a switch integrated into the
board ejection lever. This switch is activated by pushing the red bolt on top of the ejector lever.
The manual reset signal is routed across a PLD (programmable logic device) and could be
passivated on customers request.
The healthy state of the CC3-CAJUN is signalled by the LED PWR, visible either through a small
slot in the front panel, or integrated into the reset push-button. As soon as this LED begins to
shine all power voltages are well and the reset signal has been deasserted.
Another feature is the watchdog function, which can be be programmed by software. The
behaviour of the MAX6705 watchdog is partially defined by the PLD, which controls whether
the watchdog is activated. The related software (e.g. BIOS, application program) must trigger
the watchdog by toggling the GPO21 signal of the ICH2.
The watchdog is in a passive state after a system reset. There is no need to trigger it at boot
time. Once the GPO21 of the ICH2 has sent a pulse, the watchdog is activated. If the duration
between two trigger pulses exceeds a period of 1000ms, the watchdog times out and a system
reset will be generated.
The watchdog remains in the active state until the next system reset. There is no way to disable
it once it was started.
Firmware Hub (Flash BIOS)
The BIOS is stored in a 82802 compatible 8Mbit Firmware Hub (there are second sources in use
with deviant part numbers). The firmware hub contains a nonvolatile memory core based on
flash technology, allowing the BIOS to be upgraded.
The FWH can be reprogrammed (if suitable) by a DOS based tool. This program and the latest
CC3-CAJUN BIOS are available from the EKF website. Read carefully the enclosed instructions. If
the programming procedure fails e.g caused by a power interruption, the CC3-CAJUN may no
more be operable. You would have to send in the board, because the BIOS is directly soldered
to the PCB and cannot be changed by the user.