decodific.asm

Decodificacion infrarrojo con 16f628

 list      p=16f628

 __CONFIG   _CP_OFF & _WDT_OFF & _PWRTE_ON & _HS_OSC & _LVP_OFF & _MCLRE_OFF & _BODEN_ON

#include
#include "mrxv4.inc"

EXPIRE_TIMER EQU 0x12
LATCH_MASK EQU 0xff
VALID_BIT EQU 4

.mainda UDATA 0x20

savew1  res 1
savestatus res 1
savepclath res 1
savefsr  res 1
bt  res 1
expire_cnt res 1
cur_seq  res 1
cur_ch  res 1
cur_state res 1

vectors  CODE 0
    goto    main  ; go to beginning of program
  nop
  nop
  nop
     ; interrupt vector location
  goto itr

prog  CODE 5

channel_lookup  andlw 0x07
  addwf PCL, F
  dt 0x1, 0x2, 0x4, 0x8
  dt 0x10, 0x20, 0x40, 0x80

itr
 movwf savew1
 movf STATUS,w
 clrf STATUS
 movwf savestatus
 movf PCLATH,w
 movwf savepclath
 clrf PCLATH

 movf FSR,w
 movwf savefsr

 btfsc INTCON, T0IF
 call t0_int_handler

 movf savefsr,w
 movwf FSR

 movf savepclath,w
 movwf PCLATH

 movf savestatus,w
 movwf STATUS

 swapf savew1,f
 swapf savew1,w

 retfie

main
  ;HARDWARE INIT
  movlw 7
  movwf CMCON

  movlw (1<
  MOVWF PORTA
  clrf PORTB

  BANKSEL TRISA

  movlw 0x20 ; A5=input
  movwf TRISA

  MOVLW 0x0f ; B0-B3=input
  movwf TRISB

  ; setup TMR0 interrupt
  clrwdt ; changing default presc. assignment
  movlw 0x03 ; prescaler 1:16 assigned to TMR0
  movwf OPTION_REG ; T0CS selects internal CLK
  bsf INTCON, T0IE ; enable TMR0 int

  BANKSEL TMR0

  clrf TMR0

  clrf expire_cnt
  call mrx_init
  bsf INTCON, GIE

warm  clrf cur_state
  clrf cur_seq
  incf cur_seq, F

loop  call mrx_receive
  andlw 0xff
  bnz loop
  call mrx_chk_buf
  andlw 0xff
  bnz loop

  movf PORTB, W
  andlw 0x0f
  subwf (mrx_buffer), W
  bnz loop

rx_ok  movlw EXPIRE_TIMER ; indicate packet reception
  movwf expire_cnt

  movf (mrx_buffer+1), W ; if (seq==cur_seq) skip (only expire timer is updated)
  andlw 0xc0
  subwf cur_seq, W
  bz loop

  movf (mrx_buffer+1), W
  andlw 0xc0
  movwf cur_seq

  movf (mrx_buffer+1), W
  andlw 0x3f
  bz loop ; illegal channel data
  addlw 0xff
  andlw 0x0f
  movwf bt
  btfsc bt, 3
  goto loop ; ch>=8: illegal with this model
  call channel_lookup
  movwf cur_ch

  bcf INTCON, GIE
  btfsc (mrx_buffer+1), 5
  goto state_on_off

  ; 00-0f: toggle or momentary ON
  movf cur_ch, W
  andlw LATCH_MASK
  bz state_on_off ; momentary ON

state_toggle movf cur_ch, W
  xorwf cur_state, F
  goto state_done

state_on_off movf cur_ch, W
  xorlw 0xff
  andwf cur_state, F ; 20-2f: latch ON
  movf cur_ch, W
  btfss (mrx_buffer+1), 4 ; 30-3f: latch OFF
  iorwf cur_state, F
  goto state_done

state_done movlw 0
  call state_out
  bsf INTCON, GIE
  goto loop

t0_int_handler bcf INTCON, T0IF
  movf expire_cnt, F
  bnz valid_on

  movlw LATCH_MASK ; clear momentary outputs
  andwf cur_state, F
  movlw (1<< P>

state_out iorwf cur_state, W
  movwf PORTA
  movf cur_state, W
  movwf PORTB
  return

valid_on decf expire_cnt, F
  ;;bsf RX_LED
  return

  end