Kontron VMP1 with Netbootloader - Manual (Page 40)

VMP1 Functional Description
ID 26037, Rev. 01 Page 2 - 18 ® 2002 PEP Modular Computers GmbH
2.5 Special Board Features
2.5.1 Watchdog Timer
A watchdog timer is provided, which forces an NMI or Reset condition (configurable in
the watchdog register). The watchdog time can be programmed in 4 steps with a resolu-
tion of 500 ms. If the watchdog timer is enabled, it cannot be stopped or reprogrammed.
2.5.2 RTC (STC M41T56)
The Real Time Clock provides the following features:
• counters for seconds, minutes, hours, day, date, month and year.
• clock calibration by software
• low supply current for buffering with Gold Caps
• alternatively a battery may be placed on the board to buffer the RTC for a longer
time
• it is also possible to buffer the power supply for the RTC via the VME-5V-Standby
power line
• automatic leap year compensation
• precision: 35 ppm
• for greater precision or for temperature compensation the RTC can be adjusted in
in steps of +4.068 or –2.034 ppm
• for temperature compensation, the onboard temperature sensor (LM75) may be
used
2.5.3 Reset/Abort
There are also 2 push button switches with the function ABORT and RESET. The
RESET button reinitializes the board via hardware.
The ABORT button initiates the NMI. In addition it is latched into a bit in the System
Logic, the purpose of this is to differentiate between the NMI initiated from the ABORT
Button and the NMI initiated from the watchdog.
The positions of the Abort and Reset
buttons on the Front Panel may be viewed in Figure 2-2.
Table 2-7: Watchdog Time Values
Watchdog Time Values
500 ms
1 s
1.5s
2 s