Kontron AM4100, User Manual

Page: 37 / 150

AM4100 Functional Description
ID 36126, Rev. 2.0 Page 2 - 5
P R E L I M I N A R Y
2.2.2 Watchdog Timer
The AM4100 provides a Watchdog Timer that is programmable for a timeout period ranging
from 125 ms to 256 s in 12 steps. Failure to trigger the Watchdog Timer in time results in an
interrupt or a system reset. In the dual-stage mode, a combination of both interrupt and reset
is generated if the Watchdog is not serviced. A hardware status flag will be provided to deter-
mine if the Watchdog Timer generated the reset.
2.2.3 Power Monitor and Reset Generation
All onboard voltages on the AM4100 are supervised, which guarantees controlled power-up of
the board. This is done by activating a stable power-up reset signals after the threshold voltag-
es have been passed.
2.2.4 Flash Memory
There are three Flash devices available as described below, two for the NetBootLoader and
one for the NAND Flash Disk Controller.
2.2.4.1 NetBootLoader Firmware Flash (NOR Flash)
The AM4100 provides two 4 MB, redundant NetBootLoader (NBL) Firmware Flash (MirrorBit®
NOR Flash) chips. The fail-over mechanism for the Firmware recovery can be controlled via
the MMC controller or the SW2 DIP switch.
If one NBL Firmware Flash is corrupted, the MMC can enable the second NBL Firmware Flash
and boot the system again.
2.2.4.2 NAND Flash Disk Controller
The AM4100 supports up to 4 GB of NAND Flash memory in combination with the
SST55LD019 NAND Flash Disk Controller, which is connected to the MPC8641D’s local bus
controller (LBC).
The SST55LD019 NAND Flash Disk Controller provides wear-leveling algorithm to extend the
life expectancy of the connected NAND Flash.