;;
  ;;  spreadspace pic utils
  ;;
  ;;
  ;;  Copyright (C) 2011 Christian Pointner <equinox@spreadspace.org>
  ;;                         
  ;;  This file is part of spreadspace pic utils.
  ;;
  ;;  spreadspace pic utils is free software: you can redistribute it and/or modify
  ;;  it under the terms of the GNU General Public License as published by
  ;;  the Free Software Foundation, either version 3 of the License, or
  ;;  any later version.
  ;;
  ;;  spreadspace pic utils is distributed in the hope that it will be useful,
  ;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  ;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  ;;  GNU General Public License for more details.
  ;;
  ;;  You should have received a copy of the GNU General Public License
  ;;  along with spreadspace pic utils. If not, see <http://www.gnu.org/licenses/>.
  ;;
  ;; -------------------------------------
  ;; PREAMBLE

  LIST      p=16F1847
  include   "p16f1847.inc"
  __config  _CONFIG1,  _FOSC_INTOSC & _WDTE_OFF & _PWRTE_OFF & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_OFF & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF
  __config  _CONFIG2,  _WRT_OFF & _PLLEN_OFF & _STVREN_OFF & _BORV_LO & _LVP_OFF


  ;; -------------------------------------
  ;; DEFINES
CNT0 EQU H'0020'
CNT1 EQU H'0021'

  ;; -------------------------------------
  ;; OFFSET
  org	      .0
  goto      init

  ;; -------------------------------------
  ;; Interrupts
  org       .4
  clrf      BSR
  btfsc     PIR1,SSP1IF
  goto      int_spi
  retfie

int_spi
  bsf       PORTA,7
  nop
  bcf       PORTA,7
  retfie

  ;; -------------------------------------
  ;; INIT
init
  ;; BANK 4
  movlw     b'00000100'
  movwf     BSR
  movlw     b'00100100'
  movwf     SSP1CON1
  movlw     b'00010000'
  movwf     SSP1CON3
  movlw     b'00000000'
  movwf     SSP1STAT
  
  ;; BANK 3
  movlw     b'00000011'
  movwf     BSR
  clrf      ANSELA
  clrf      ANSELB

  ;; BANK 2
  movlw     b'00000010'
  movwf     BSR

  ;; BANK 1
  movlw     b'00000001'
  movwf     BSR  
  movlw     b'01111111'
  movwf     TRISA
  movlw     b'01110011'
  movwf     TRISB
  movlw     b'01011000'
  movwf     OSCCON
  movlw     b'00001000'
  movwf     PIE1
  movlw     b'01000000'
  movwf     INTCON
  
  ;; BANK 0
  clrf      BSR
  clrf      PIR1
  bsf       INTCON,GIE
  bcf       PORTA,7

  ;; -------------------------------------
  ;; MAINLOOP
main
  movlw     .50
  movwf     CNT0

outer
  movlw     .255
  movwf     CNT1

inner
  decfsz    CNT1,f
  goto      inner

  decfsz    CNT0,f
  goto      outer

  movlw     b'00001000'
  xorwf     PORTB,f

  goto	    main

  ;; -------------------------------------
  ;; END
  end