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4.7 PNP/PCI Configuration
The PNP/PCI Configuration help user handles the JUKI-6752
board‘s “PCI” function. All PCI bus slots on the system use
INTA#,thus all installed PCI slots must be set to this value..
PNP OS Installed : Yes or No
When PNP OS is installed, interrupts may be reassigned by the OS
when the setting is Yes. When a non-PNP OS is installed or to
prevent reassigning of interrupt settings, select setting to No.
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Appendix A. Watch-Dog Timer
The WatchDog Timer is a device to ensure that standalone systems can
always recover from abnormal conditions that cause the system to crash.
These conditions may result from an external EMI or a software bug. When
the system stops working, hardware on the board will perform hardware
reset (cold boot) to bring the system back to a known state.
Three I/O ports control the operation of WatchDog Timer.
443 (hex)
Write
Set WatchDog Time period
443 (hex)
Read
Enable the refresh the WatchDog Timer.
043/843 (hex)
Read
Disable the WatchDog Timer.
Prior to enable the WatchDog Timer, user has to set the time-out period.
The resolution of the timer is 1 second and the range of the timer is from 1
sec to 255 sec. You need to send the time-out value to the I/O port – 443H,
and then enable it by reading data from the same I/O port – 443H. This will
activate the timer that will eventually time out and reset the CPU board. To
ensure that this reset condition won’t occur, the WatchDog Timer must be
periodically refreshed by reading the same I/O port 443H. This must be
done within the time-out period that is set by the software, please refer to
the example program. Finally, we have to disable the WatchDog timer by
reading the I/O port -- 843H or 043H. Otherwise the system could reset
unconditionally.
A tolerance of at least 5% must be maintained to avoid unknown routines in the
operating system (DOS), such as disk I/O that can be very time-consuming.
Therefore if the time-out period has been set to 10 seconds, the I/O port 443H
must be read within 7 seconds
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Summary of Contents for JUKI-6752
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