VIPA PC-CPU 486, Manual

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Chapter 3 BIOS / Register Manual VIPA PC-CPU 486
3-12 HB111E - Rev. 02/32
(I/O address range 270h-277h)
The Watchdog is turned off when the system has started or has been reset
and it can be enabled under software control.
The Watchdog register is controlled via I/O address 270h and the following
parameters:
Watchdog on load 40h after address 270h
Watchdog off load 50h after address 270h
Watchdog trigger load 60h after address 270h
and then
load 70h after address 270h
The Watchdog must be triggered when the power has been turned on. The
triggering time is programmable:
Parameter for triggering time I/O-register 290h R/W (enabled via 293h).
The trigger time is a multiple of 147ms and has to be entered in the
register 290h Watchdog time. As soon as you load the register 290h with
00h, the Watchdog timer is deactivated.
Please regard, that you have to enable write access for the register
Watchdog time.
The following sequences to the register 293h are activating resp.
deactivating the write access to the registers 290h and 292h.
Enable write access: 03h, 06h, 03h, 00h
Disable write access: 03h, 06h, 03h, 01h
Note!
After reset the write access to 290h and 292h is inhibited.
The serial number can be found in the registers 271h and 272h.
More detailed information about the I/O port 285h is available at VIPA.
The C165 control register I/O port 292h R/W (release via 293h) are
reserved for download purposes.
Watchdog
Trigger time
Serial number
EEPROM
C165
Control register