;;
  ;;  mur.sat
  ;;
  ;;  Somewhen in the year 2011, mur.at will have a nano satellite launched
  ;;  into a low earth orbit (310 km above the surface of our planet). The
  ;;  satellite itself is a TubeSat personal satellite kit, developed and
  ;;  launched by interorbital systems. mur.sat is a joint venture of mur.at,
  ;;  ESC im Labor and realraum.
  ;;
  ;;  Please visit the project hompage at sat.mur.at for further information.
  ;; 
  ;;
  ;;  Copyright (C) 2011 Christian Pointner <equinox@mur.at>
  ;;                         
  ;;  This file is part of mur.sat.
  ;;
  ;;  mur.sat 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.
  ;;
  ;;  mur.sat 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 mur.sat. If not, see <http://www.gnu.org/licenses/>.
  ;;
  ;; -------------------------------------
  ;; PREAMBLE

  LIST      p=16F887
  include   "p16f887.inc"
  __config  _CONFIG1,  _DEBUG_OFF & _LVP_OFF & _FCMEN_OFF & _IESO_OFF & _BOR_NSLEEP & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _XT_OSC
  __config  _CONFIG2,  _BOR21V & _WRT_OFF
  
  ;; -------------------------------------
  ;; DEFINES
  ;;   constants
  
  ;;   I/O Pins
DTMF_D0     EQU 0
DTMF_D1     EQU 1
DTMF_D2     EQU 2
DTMF_D3     EQU 3
DTMF_PWRDWN EQU 4
TTX_RESET   EQU 5
TTX_SCL     EQU 6
TTX_SDA     EQU 7
  
  ;;   variables
  ;;     page 0 only
TMP         EQU H'0020'

  ;;     all pages
W_TEMP      EQU H'007E'
STATUS_TEMP EQU H'007F'

  ;;    bits 
  
  ;; -------------------------------------
  ;; Reset Vector
  org	      0
  goto      init

  ;; -------------------------------------
  ;; Interrupt Vector
  org	      4
  ;; save context
  movwf     W_TEMP
  swapf     STATUS,W
  movwf     STATUS_TEMP

  bcf       STATUS,RP0
  bcf       STATUS,RP1

  btfsc     PIR1,RCIF
  goto      int_uart_rx
  goto      interrupt_end

int_uart_rx
  call      uart_rx_byte
  btfsc     PIR1,RCIF
  call      uart_rx_byte
  btfss     RCSTA,OERR
  goto      int_uart_rx_oe
  goto      interrupt_end
  
int_uart_rx_oe
  bcf       RCSTA,CREN
  bsf       RCSTA,CREN
  
interrupt_end
  ;; restore context
  swapf     STATUS_TEMP,W
  movwf     STATUS
  swapf     W_TEMP,F
  swapf     W_TEMP,W
  retfie

  ;; -------------------------------------
  ;; INIT
init
  ;; bank 3
  bsf       STATUS,RP0
  bsf       STATUS,RP1
  movlw     b'00000000'
  movwf     BAUDCTL

  ;; bank 1
  bsf       STATUS,RP0
  bcf       STATUS,RP1
  movlw     b'11000111'
  movwf     OPTION_REG
  clrf      PSTRCON
  movlw     b'00010000'
  movwf     OSCCON
  movlw     b'00001111'
  movwf     TRISD
  movlw     b'00100100'
  movwf     TXSTA
  movlw     .12
  movwf     SPBRG
  clrf      SPBRGH
  movlw     b'00100000'
  movwf     PIE1
  clrf      PIE2
  
  ;; bank 0
  bcf       STATUS,RP0 
  bcf       STATUS,RP1
  movlw     b'10010000'
  movwf     RCSTA
  movlw     B'01000000'
  movwf     INTCON
  
  bcf       PORTD,TTX_RESET     ;reset TTX
  nop
  nop
  bsf       PORTD,TTX_RESET
  clrf      TMR0  

  bsf       INTCON,GIE
  movlw     .1
  movwf     TMP
  goto      main

  ;; -------------------------------------
  ;; TABLES

  ;; TODO: add lookup tables if needed
  
  ;; -------------------------------------
  ;; SUBROUTINES
uart_rx_byte
  btfsc     RCSTA,FERR
  goto      uart_rx_fe
  movf      RCREG,w             ; TODO: move to input string
  movwf     TXREG
  bsf       TMP,0
  return

uart_rx_fe
  movf      RCREG,w
  return
  
  ;; -------------------------------------
  ;; MAINLOOP
main
  btfss     TMP,0
  goto      main

  bcf       TMP,0
  bcf       PORTD,DTMF_PWRDWN
  bcf       INTCON,T0IF
  clrf      TMR0
loop
  btfss     INTCON,T0IF
  goto      loop
  bsf       PORTD,DTMF_PWRDWN
  goto      main
  
powerdown
  sleep
  nop
  goto      main
  
  ;; -------------------------------------
  ;; END
  end