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DEF6821.LIB
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Text File
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2000-06-30
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2KB
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49 lines
;** 6821 PERIPHERAL INTERFACE ADAPTER EQUATES
;
; REGISTER DISPLACEMENTS
PIADATA EQU 0 ;PERIPHERAL DATA REGISTER A
PIADDRA EQU 0 ;DATA DIRECTION REGISTER A
PIACTLA EQU 1 ;CONTROL REGISTER A
PIADATB EQU 2 ;PERIPHERAL DATA REGISTER B
PIADDRB EQU 2 ;DATA DIRECTION REGISTER B
PIACTLB EQU 3 ;CONTROL REGISTER B
; CONTROL WORD FORMAT
PIAC1 EQU 00000011B ;CONTROL OF CA1(CB1) INTERRUPT LINE
PIAC10 EQU 00H ; ACTIVE TRANSITION 1->0
; IRQ PIN IS DISABLED
PIAC11 EQU 01H ; ACTIVE TRANSITION 1->0
; IRQ PIN IS ENABLED
PIAC12 EQU 02H ; ACTIVE TRANSITION 0->1
; IRQ PIN IS DISABLED
PIAC13 EQU 03H ; ACTIVE TRANSITION 0->1
; IRQ PIN IS ENABLED
PIADDAC EQU 00000100B ;DATA DIRECTION ACCESS CONTROL BIT
; 0=DATA DIRECTION REG , 1=PERIPHERAL DATA REG
PIAC2 EQU 00111000B ;CONTROL OF CA2(CB2)
; INPUT MODES
PIAC20 EQU 00H ; ACTIVE TRANSITION 1->0
; IRQ PIN IS DISABLED
PIAC21 EQU 08H ; ACTIVE TRANSITION 1->0
; IRQ PIN IS ENABLED
PIAC22 EQU 10H ; ACTIVE TRANSITION 0->1
; IRQ PIN IS DISABLED
PIAC23 EQU 18H ; ACTIVE TRANSITION 0->1
; IRQ PIN IS ENABLED
; OUTPUT MODES
PIAC24 EQU 20H ; 0 ON R(W) OPERATION , 1 ON ACTIVE CA1(CB1)
PIAC25 EQU 28H ; 0 ON R(W) OPERATION , 1 ON E AFTER DESELECT
PIAC26 EQU 30H ; RESET
PIAC27 EQU 38H ; SET
PIAIRQ2 EQU 01000000B ;IRQ FOR CA2(CB2)
PIAIRQ1 EQU 10000000B ;IRQ FOR CA1(CB1)