UPD780076GC-XXX-AB8 データシートの表示（PDF） - NEC => Renesas Technology
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UPD780076GC-XXX-AB8 Datasheet PDF : 415 Pages
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CHAPTER 13 APPLICATIONS OF KEY INPUT
(4) Program list
PUBLIC KEYDATA,KEYCHG,KEYIN,CHATCT
KEY_DAT DSEG
KEYDATA:DS
WORK: DS
CHATCT: DS
WORKCT: DS
SADDR
4
4
1
1
; Key data storage area
; Chattering key data
; Chattering counter
KEY_FLG BSEG
CHGFG DBIT
KEYCHG DBIT
CHTEND DBIT
; Key change status
; Key changed
; Chattering absorption end status
KEY_SEG CSEG
;*******************************
*
Matrix key input
;*******************************
KEYIN:
CLR1 CHGFG
P3&=#00001111B
P3|=#00010000B
HL=#WORK
repeat
A=P4
A^=#11111111B
if(A!=[HL])
SET1 CHGFG
[HL]=A
endif
HL++
A=P3
A&=#11110000B
X=A
A=P3
A+=X
P3=A
until_bit(CY)
; Sets address of key work area
; Data inverted
; Key changed?
; Shifts key scan 1 bit
if_bit(!CHGFG)
if_bit(!CHTEND)
CHATCT--
if(CHATCT==#0)
SET1 CHTEND
DE=#WORK
HL=#KEYDATA
for(WORKCT=#0;WORKCT<#4;WORKCT++)
if([DE]!=[HL]) (A)
SET1 KEYCHG
endif
A<->[HL]
HL++
DE++
next
endif
endif
else
CHATCT=#3
CLR1 CHTEND
endif
RET
; Key changed
; Chattering absorbed
; Chattering ends
; Key changed
; Transfers WORK to KEYDATA
377
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