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90 lines
1.6 KiB
90 lines
1.6 KiB
10 years ago
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.device attiny13
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.def cnt=r22
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.def i=r18
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.def j=r19
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.def pom=r16
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.def dat=r20
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.equ clks=200 ;100 kloknuti (36kHz) na 1 bit (200 preklopeni)
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.equ clksh=100
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.org 0x0000 ;RESET
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rjmp RESET ;skok na start po resetu
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.org 0x0010
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RESET:
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ldi r16,low(RAMEND) ;nastavi stack pointer
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out SPL,r16
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cli ;zakazeme preruseni
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ldi r16,0b00011110 ;smer portu
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out DDRB,r16
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clr pom
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clr i
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clr j
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clr cnt
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sei ;povolime preruseni
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NIC: clr i
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clr dat
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W0: in pom,PINB ;1 [10+56 =66 cyklu *clksh celkani]
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sbrc pom,0 ;2 /
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rjmp NIC ;(1)
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rcall sclk ;3
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inc i ;1
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cpi i,clksh ;1
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brne W0 ;2 10 kloku + 56 kloku z sclk = 66 kloku
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;bylo 100 kloku 0
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ldi j,8 ;1 -> bude se cist osm bitu
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BREAD: dec j ;1
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breq ENDB ;1
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clr i ;1
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W1: nop ;1 -> cekaci smycka 1klok
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nop ;1
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nop ;1
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rcall sclk ;3
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inc i ;1
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cpi i,clks ;1
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brne W1 ;2
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in pom,PINB ;1 zanedbatelne zpozdeni - netreba zohlednovat
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sbrs pom,0 ;2 (1) precte se PINB0 a invertovany se zapise do bufferu
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sbr dat,0 ;(+1)
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lsl dat ;1
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rjmp BREAD ;2
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ENDB:
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;skoncil byte, ted bude stopbit - netreba cist
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cpi dat,0b00111100
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breq toogle
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clr dat
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clr cnt
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clr i
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clr j
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rjmp NIC
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toogle: sbi PORTB,1
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;sbi pinb,1
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rjmp NIC
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sclk: ;presne nastavena doba jednoho kloku - 200 kloku == 1bit
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ldi r16,6 ;1
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cB:
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nop ; [48
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nop ; -
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nop ; -
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nop ; -
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nop ; -
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dec r16 ; -
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brne cB ; -
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nop ; ]
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nop ;3
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nop ;
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nop ;
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ret ;4 celkem: 56
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