Some old AVR projects
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89 lines
1.6 KiB

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