RC5_decoder_by_unknown

услуги электронщика

                              ;Это полностью рабочий код приёмника RC5 - проверенно!

.include "C:\Avrtools\appnotes\2313def.inc"
.device AT90S1200 


.equ INPUT=0                  ;PD2
.equ SYS_ADDR=0               ;The system address 


.def S=R0
.def inttemp=R1
.def ref1=R2
.def ref2=R3 

.def temp=R16 

.def timerL=R17
.def timerH=R16 

.def system=R19
.def command=R20 

.def bitcnt=R21 


.cseg
.org 0
 rjmp reset 


.org OVF0addr

TIM0_OVF: 
       in S,sreg
       inc timerL             ;Updated every 64us
       inc inttemp
       brne TIM0_exit 
       inc timerH 

TIM0_exit: 
       out sreg,S
       reti 




reset: 
       ldi temp,0b00000001    ;Timer/Counter 0 clocked at CK
       out TCCR0,temp 

       ldi temp,1< 
       out TIMSK,temp 

       ldi temp,0b11111111    ;PORTB as output
       out DDRB,temp 

       sei                    ;Enable gobal iterrupt 


main: 
       rcall detect           ;Call RC5 detect routine 

       cpi system,SYS_ADDR    ;Respponds only at the specified address
       brne release 

       andi command,0x3F      ;Remove control bit
       out PORTB,command 

       rjmp main 


release: 
       clr command            ;Clear PORTB
       out PORTB,command
       rjmp main 



detect: 
       clr inttemp
       clr timerH 

detect1: 
       clr timerL 

detect2: 
       cpi timerH,8           ;If line not idle within 131ms
       brlo dl1
       rjmp fault             ;then exit 

dl1: 
       cpi timerL,55          ;If line low for 3.5ms
       brge start1            ; then wait for start bit 

       sbis PIND,INPUT        ;If line is
       rjmp detect1           ; low - jump to detect1
       rjmp detect2           ; high - jump to detect2 


start1: 
       cpi timerH,8           ;If no start bit detected
       brge fault             ;within 130ms then exit 

       sbic PIND,INPUT        ;Wait for start bit
       rjmp start1 


       clr timerL             ;Measure length of start bit

start2: 
       cpi timerL,17          ;If startbit longer than 1.1ms,
       brge fault             ; exit 

       sbis PIND,INPUT
       rjmp start2
                              ;Positive edge of 1st start bit 

       mov temp,timerL        ;timer is 1/2 bit time
       clr timerL 

       mov ref1,temp
       lsr ref1
       mov ref2,ref1
       add ref1,temp          ;ref1 = 3/4 bit time
       lsl temp
       add ref2,temp          ;ref2 = 5/4 bit time 


start3: 
       cp timerL,ref1         ;If high periode St2 > 3/4 bit time
       brge fault             ;exit 

       sbic PIND,INPUT        ;Wait for falling edge start bit 2
       rjmp start3 

       clr timerL
       ldi bitcnt,12          ;Receive 12 bits
       clr command
       clr system 


sample: 
       cp timerL,ref1         ;Sample INPUT at 1/4 bit time
       brlo sample 

       sbic PIND,INPUT
       rjmp bit_is_a_1        ;Jump if line high 


bit_is_a_0: 
       clc                    ;Store a '0'
       rol command
       rol system 

                              ;Synchronize timing
bit_is_a_0a: 
       cp timerL,ref2         ;If no edge within 3/4 bit time
       brge fault             ;exit
       sbis PIND,INPUT        ;Wait for rising edge
       rjmp bit_is_a_0a       ;in the middle of the bit 

       clr timerL
       rjmp nextbit 

bit_is_a_1: 
       sec                    ;Store a '1'
       rol command
       rol system
                              ;Synchronize timing
bit_is_a_1a: 
       cp timerL,ref2         ;If no edge within 3/4 bit time
       brge fault             ;exit
       sbic PIND,INPUT        ;Wait for falling edge
       rjmp bit_is_a_1a       ;in the middle of the bit 

       clr timerL 

nextbit: 
       dec bitcnt             ;If bitcnt > 0
       brne sample            ;get next bit 


       mov temp,command       ;Place system bits in "system"
       rol temp
       rol system
       rol temp
       rol system 

       bst system,5           ;Move toggle bit
       bld command,6          ;to "command" 

                              ;Clear remaining bits
       andi command,0b01111111
       andi system,0x1F 

       ret 

fault: 
       ser command            ;Both "command" and "system"
       ser system             ;0xFF indicates failure
       ret