Global American 3304030, User Manual

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3304030 User’s Manual Appendix C
Appendix C <Watchdog Timer Programming Guide>
WDT source from : Wi nBond 83627HF
(1) General Description
Winbond has a WDT feature inside its chip. We implement its
function i nto our circuit .
There are many configuration Registors ( CR ) in 83627HF. The
following sequence must be followed for CR programming :
(*1) E nter the extended function mode
(*2) Configure the configuration registers
(*3) E xit the extended function mode
EFER : E xtended F unction Enable Registers.( EFER=2Eh in our system )
EFIR : Extended F unction Index Register. ( Same addr. with EFER. ) EFDR :
E xtended F unction Data Register.( Located at addr.[ EF IR +1 ] )
For instance ;
(*1) E nter extended function mode
MOV DX,2EH
MOV AL,87H
CLI ; disable interrupt
OUT DX,AL
JMP $+2
OUT DX,AL
STI ; enable i nterrupt
(*2) Configurate logical device 1 , configuration register CRF0
MOV DX,2EH
MOV AL,07H
OUT DX,AL
; point to Logical Device Number Register
MOV DX,2FH
MOV AL,01H
OUT DX,AL
MOV DX,2EH
MOV AL,0F0H
OUT DX,AL
MOV DX,2FH
MOV AL,3CH
; select logical device 1
OUT DX,AL ; update CRF0 of LD0 with value 3C h
(*3) E xit extended function mode
MOV DX,2EH
MOV AL,0AAH
OUT DX,AL
The Configuration Register ( CR ) Defi nition :
Watchdog Timer Programming Guide
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