CPU 1021/A
User’s Guide
10
Asem S.p.A.
3.
Run
waiting for command out 566h=nh (0<
n
<=FFh), to refresh the
WD, resetting the timer count. If there is no refresh and the timer
expires, it changes to Expired.
4.
Expired
after the watch-dog timer has expired:
•
the watch-dog LED on the CPU 1021/A will come on
•
bit 0 of the port I/O 568h (watch-dog in Expired state) will be
set to logic state
1.
The application software will
subsequently be able to read it.
•
There will then be generated a
Reset
, based on the settings
made by the user.
To change back from
Expired
state to
Idle
it is necessary:
-
To set logic state
0
for bit 0 of port 568h
-
To set logic state
0
for the 8 bits of port 566h
To turn off the watch-dog LED it is necessary to press
Reset watch-
dog button.
Summary of commands
The watch-dog is capable of receiving the following commands from
the application software:
Command
Effect
out 565h, 80h
Changes the watch-dog from Idle state to Set
out 566h, nh (0<n<=FFh)
Switches state "Set" to "Run" and also must be
periodically issued while the WD is in a state of
"Run" to make a refreshing and avoid the time-out.
out 568h, 0h
converts the bit 0 of port 568h to 0 (zero bit
indicates that WD Expired)
out 566h, 0h
Goes from "Expired" to "Idle" and is ready to be
rearmed.
The addresses of I / O mentioned refer to the programming carried
by the version of BIOS 8921965A.04. To obtain the values
programmed by earlier versions add 180h to any address.
Содержание CPU 1021/A
Страница 1: ...86040332 CPU 1021 A ...
Страница 2: ......
Страница 7: ...Exit menu 60 ...
Страница 8: ......
Страница 9: ...Description Asem S p A 1 Chapter 1 Description ...
Страница 20: ...CPU 1021 A User s Guide 12 Asem S p A ...
Страница 22: ...CPU 1021 A User s Guide 14 Asem S p A Layout CPU 1021 A with highlighting of jumpers CPU 1021 A part A ...
Страница 23: ...Hardware setup Asem S p A 15 CPU 1021 A part B ...
Страница 27: ...Connectors Asem S p A 19 Chapter 3 Connectors Layout CPU 1021 A with connectors and switches highlighted ...
Страница 29: ...Connectors Asem S p A 21 CPU 1021 A front part B ...
Страница 30: ...CPU 1021 A User s Guide 22 Asem S p A CPU 1021 A rear part A ...
Страница 31: ...Connectors Asem S p A 23 CPU 1021 A rear part B ...
Страница 45: ...Map of memory Asem S p A 37 Chapter 4 Map of memory ...
Страница 49: ...BIOS Setup Asem S p A 41 Chapter 5 BIOS Setup ...