path: root/software/idm/idm.asm

  ;;
  ;;  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 & _INTRC_OSC_CLKOUT
  __config  _CONFIG2,  _BOR21V & _WRT_OFF
  
  ;; -------------------------------------
  ;; DEFINES
  ;;   constants
BUF_PAGE_LEN  EQU H'0050'
BUF_PAGE_CNT  EQU H'0004'
BUF_OFFSET    EQU H'0020'

  ;; FLAGS
UNDERRUN      EQU .0
OVERRUN       EQU .1

CTS           EQU .7
  
  ;; I/O Pins
;; PortA
DBG1          EQU .4
DBG2          EQU .5
;; PortC

  
  ;; variables
  ;;     page 0 only
  
  
  ;;     all pages
RX_BYTE       EQU H'0070'
WAIT_CNT      EQU H'0071'
FLAGS         EQU H'0072'
  
WBUF_PAGE_PTR EQU H'0074'
WBUF_PAGE_NUM EQU H'0075'
RBUF_PAGE_PTR EQU H'0076'
RBUF_PAGE_NUM EQU H'0077'
  
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

  ;;  dispatch interrupt sources
  btfsc     PIR1,TMR2IF
  goto      int_tmr2
  btfsc     PIR1,RCIF
  goto      int_uart_rx
  btfsc     PIR1,TXIF
  goto      int_uart_tx
  goto      interrupt_end

int_tmr2
  bsf       ADCON0,GO

  bsf       STATUS,RP0
  btfss     FLAGS,CTS
  bcf       PIE1,TXIE
  btfsc     FLAGS,CTS
  bsf       PIE1,TXIE
  bcf       STATUS,RP0

int_tmr2_adcon
  btfsc     ADCON0,GO
  goto      int_tmr2_adcon

  call      wbuf_next
  btfsc     FLAGS,OVERRUN
  goto      int_tmr2_end
  movf      ADRESH,w
  movwf     INDF
  
int_tmr2_end
  bcf       PIR1,TMR2IF
  goto      interrupt_end
  

int_uart_tx
  call      rbuf_next
  btfsc     FLAGS,UNDERRUN
  goto      interrupt_end
  movf      INDF,w
  movwf     TXREG
  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

  goto      interrupt_end


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
  movlw     b'00100000'
  movwf     ANSEL

  ;; bank 2
  bcf       STATUS,RP0
  bsf       STATUS,RP1
  movlw     b'10000000'
  movwf     CM1CON0
  movlw     b'10010000'
  movwf     CM2CON0
  
  ;; bank 1
  bsf       STATUS,RP0
  bcf       STATUS,RP1
  movlw     b'10000010'
  movwf     OPTION_REG
  clrf      PSTRCON
  movlw     b'01111000'
  movwf     OSCCON
  movlw     b'11001111'
  movwf     TRISA
  movlw     b'11111111'
  movwf     TRISB
  movlw     b'11111111'
  movwf     TRISC
  movlw     b'11111111'
  movwf     TRISD
  movlw     b'00100100'
  movwf     TXSTA
  movlw     .8
  movwf     SPBRG
  clrf      SPBRGH
  movlw     b'00100010'
  movwf     PIE1
  clrf      PIE2
;  movlw     .250        ;; 8kHz
  movlw     .200        ;; 5kHz
;  movlw     .156        ;; ~50Hz / ~200Hz
  movwf     PR2
  clrf      ADCON1
  
  ;; bank 0
  bcf       STATUS,RP0 
  bcf       STATUS,RP1
  movlw     b'10010000'
  movwf     RCSTA
;  movlw     b'00000100' ;; 8kHz
  movlw     b'00001100' ;; 5kHz
;  movlw     b'01111110' ;; ~50Hz
;  movlw     b'01111101' ;; ~200Hz
  movwf     T2CON
  movlw     b'01000000'
  movwf     INTCON
  clrf      TMR2
  movlw     b'10010101'
  movwf     ADCON0
  
  bcf       PORTA,DBG1
  bcf       PORTA,DBG2

  call      wbuf_reset
  call      rbuf_reset
  clrf      RX_BYTE
  bsf       INTCON,GIE

  goto      main


  ;; -------------------------------------
  ;; TABLES
digit
  addwf     PCL,f
  retlw     '0'
  retlw     '1'
  retlw     '2'
  retlw     '3'
  retlw     '4'
  retlw     '5'
  retlw     '6'
  retlw     '7'
  retlw     '8'
  retlw     '9'
  retlw     'A'
  retlw     'B'
  retlw     'C'
  retlw     'D'
  retlw     'E'
  retlw     'F'


  ;; -------------------------------------
  ;; SUBROUTINES
wait_ms
  movwf     WAIT_CNT
wait_next
  movlw     .6
  movwf     TMR0
  bcf       INTCON,T0IF
wait_loop
  btfss     INTCON,T0IF
  goto      wait_loop
  decfsz    WAIT_CNT,f
  goto      wait_next
  return

  ;; -------------------
uart_rx_byte
  btfsc     RCSTA,FERR
  goto      uart_rx_fe
  movf      RCREG,w             ; TODO: move to input string
  movwf     RX_BYTE
  return

uart_rx_fe
  movf      RCREG,w
  return

  ;; -------------------
wbuf_reset
  movlw     BUF_PAGE_LEN - 1
  movwf     WBUF_PAGE_PTR
  movlw     BUF_PAGE_CNT - 1
  movwf     WBUF_PAGE_NUM
  bcf       FLAGS,OVERRUN
  bcf       PORTA,DBG1

  
  ;; -------------------
wbuf_next
  btfsc     FLAGS,UNDERRUN
  goto      wbuf_move_ptr
  
  movf      RBUF_PAGE_NUM,w
  xorwf     WBUF_PAGE_NUM,w
  btfss     STATUS,Z
  goto      wbuf_move_ptr

  movf      RBUF_PAGE_PTR,w
  xorwf     WBUF_PAGE_PTR,w
  btfss     STATUS,Z
  goto      wbuf_move_ptr

  bsf       FLAGS,OVERRUN
  bsf       PORTA,DBG1

  return
  
wbuf_move_ptr
  bcf       FLAGS,UNDERRUN
  bcf       PORTA,DBG2
  bsf       STATUS,RP0
  btfsc     FLAGS,CTS
  bsf       PIE1,TXIE
  bcf       STATUS,RP0

  movf      WBUF_PAGE_PTR,f
  btfsc     STATUS,Z
  goto      wbuf_next_page
  decf      WBUF_PAGE_PTR,f
  goto      wbuf_fill_fsr

wbuf_next_page
  movlw     BUF_PAGE_LEN - 1
  movwf     WBUF_PAGE_PTR
  movf      WBUF_PAGE_NUM,f
  btfsc     STATUS,Z
  goto      wbuf_next_cycle
  decf      WBUF_PAGE_NUM,f
  goto      wbuf_fill_fsr

wbuf_next_cycle
  movlw     BUF_PAGE_CNT - 1
  movwf     WBUF_PAGE_NUM
  
wbuf_fill_fsr
  movlw     BUF_OFFSET
  addwf     WBUF_PAGE_PTR,w
  movwf     FSR

  btfss     WBUF_PAGE_NUM,0
  bcf       FSR,7
  btfsc     WBUF_PAGE_NUM,0
  bsf       FSR,7
  btfss     WBUF_PAGE_NUM,1
  bcf       STATUS,IRP
  btfsc     WBUF_PAGE_NUM,1
  bsf       STATUS,IRP
  return

    ;; -------------------
rbuf_reset
  movlw     BUF_PAGE_LEN - 1
  movwf     RBUF_PAGE_PTR
  movlw     BUF_PAGE_CNT - 1
  movwf     RBUF_PAGE_NUM
  bsf       FLAGS,UNDERRUN
  bsf       PORTA,DBG2

  bsf       STATUS,RP0
  bcf       PIE1,TXIE
  bcf       STATUS,RP0

  bcf       FLAGS,CTS
  
  ;; -------------------
rbuf_next
  btfsc     FLAGS,OVERRUN
  goto      rbuf_move_ptr

  movf      WBUF_PAGE_NUM,w
  xorwf     RBUF_PAGE_NUM,w
  btfss     STATUS,Z
  goto      rbuf_move_ptr

  movf      WBUF_PAGE_PTR,w
  xorwf     RBUF_PAGE_PTR,w
  btfss     STATUS,Z
  goto      rbuf_move_ptr

  bsf       FLAGS,UNDERRUN
  bsf       PORTA,DBG2
  bsf       STATUS,RP0
  bcf       PIE1,TXIE
  bcf       STATUS,RP0

  return
  
rbuf_move_ptr
  bcf       FLAGS,OVERRUN
  bcf       PORTA,DBG1

  movf      RBUF_PAGE_PTR,f
  btfsc     STATUS,Z
  goto      rbuf_next_page
  decf      RBUF_PAGE_PTR,f
  goto      rbuf_fill_fsr

rbuf_next_page
  movlw     BUF_PAGE_LEN - 1
  movwf     RBUF_PAGE_PTR
  movf      RBUF_PAGE_NUM,f
  btfsc     STATUS,Z
  goto      rbuf_next_cycle
  decf      RBUF_PAGE_NUM,f
  goto      rbuf_fill_fsr

rbuf_next_cycle
  movlw     BUF_PAGE_CNT - 1
  movwf     RBUF_PAGE_NUM
  
rbuf_fill_fsr
  movlw     BUF_OFFSET
  addwf     RBUF_PAGE_PTR,w
  movwf     FSR

  btfss     RBUF_PAGE_NUM,0
  bcf       FSR,7
  btfsc     RBUF_PAGE_NUM,0
  bsf       FSR,7
  btfss     RBUF_PAGE_NUM,1
  bcf       STATUS,IRP
  btfsc     RBUF_PAGE_NUM,1
  bsf       STATUS,IRP
  return


  ;; -------------------------------------
  ;; MAINLOOP
main
  movlw     'r'
  xorwf     RX_BYTE,w
  btfsc     STATUS,Z
  goto      cmd_read    
  movlw     'n'
  xorwf     RX_BYTE,w
  btfsc     STATUS,Z
  goto      cmd_noread    
  movlw     's'
  xorwf     RX_BYTE,w
  btfsc     STATUS,Z
  goto      cmd_start    
  movlw     'p'
  xorwf     RX_BYTE,w
  btfsc     STATUS,Z
  goto      cmd_stop
  goto      main

cmd_read
  bsf       FLAGS,CTS
  clrf      RX_BYTE
  goto      main

cmd_noread
  bcf       FLAGS,CTS
  clrf      RX_BYTE
  goto      main

cmd_start
  ;; start sampling
  ;; bsf       FLAGS,CTS
  clrf      RX_BYTE
  goto      main

cmd_stop 
  clrf      RX_BYTE
  goto      main
  
powerdown
  sleep
  nop
  goto      main
  
  ;; -------------------------------------
  ;; END
  end