B&B Electronics ATRWDT Benutzerhandbuch
10
Documentation Number ATxWDT-1303
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Comm. Pk – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
The four bit latch values are also readable. Reading these bits is
recommended to verify the presence and setup of the WDT. The
BASIC command INP <WDTaddress> is used to read from the
WDT. The top three bits are not used and can be masked out. In the
ATRWDT the fifth bit is the reset flag. It will be a 1 when the
ATRWDT resets the computer and a 0 if the computer has not been
reset by the ATRWDT. This bit will be cleared if the computer is
turned off or after the bit has been read. A small example program,
written in QuickBASIC can be found in Appendix B.
BASIC command INP <WDTaddress> is used to read from the
WDT. The top three bits are not used and can be masked out. In the
ATRWDT the fifth bit is the reset flag. It will be a 1 when the
ATRWDT resets the computer and a 0 if the computer has not been
reset by the ATRWDT. This bit will be cleared if the computer is
turned off or after the bit has been read. A small example program,
written in QuickBASIC can be found in Appendix B.
Table 4. Registers
Write Register
Read Register
L0
L0
L1
L1
L2
L2
L3
L3
X
Reset Flag FOR ATR
X FOR ATX
X
X
X
X
X
X
X = Don’t Care
Pinouts
Three pins of the male DB-9 connector are used for the WDT.
Pins 4 and 7 are the external device reset relay contacts. These are
non-polarized, normally open contacts, and pins 3 and 7 are for the
normally closed.
non-polarized, normally open contacts, and pins 3 and 7 are for the
normally closed.
Figure 2 is a schematic of the output portion of the WDT.