Kontron VMP1 with Netbootloader Manuel d'utilisateur télécharger pdf (Page 40)

VMP1 Functional Description

ID 26037, Rev. 01Page 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

1 2 ... 35 36 37 38 39 40 41 42 43 44 45 ... 119 120

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Kontron VMP1 with Netbootloader Manuel d'utilisateur Page 40