;;
  ;;  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=16F887
  include   "p16f887.inc"
  ;; __config  _CONFIG1,  _DEBUG_OFF & _LVP_OFF & _FCMEN_OFF & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_OFF & _WDT_OFF & _XT_OSC
  ;; __config  _CONFIG2,  _BOR21V & _WRT_256

  ;; -------------------------------------
  ;; DEFINES
#define         BOOTPIN   PORTC,7
USERVECT        EQU       H'100'
ISRVECT         EQU       USERVECT + H'4'
FSS             EQU       8

E_OK            EQU       0
E_INV_CMD       EQU       1
E_BAD_CSUM      EQU       2
E_NOT_IMPL      EQU       3
E_FLASH_WERR    EQU       4
E_ADDR_INVALID  EQU       5
E_ADDR_PROHIB   EQU       6

CMD_IDENTIFY    EQU       'i'
CMD_BOOT        EQU       'b'
CMD_RESET       EQU       'r'
CMD_R_FLASH     EQU       'f'
CMD_W_FLASH     EQU       'F'
CMD_R_EEPROM    EQU       'e'
CMD_W_EEPROM    EQU       'E'
CMD_R_CONFIG    EQU       'c'
CMD_W_CONFIG    EQU       'C'


  ;; -------------------------------------
  ;; Boot test
  org	    0
  btfsc     BOOTPIN
  goto      USERVECT
  goto      boot

  ;; -------------------------------------
  ;; goto user ISR
  org       4
isr
  goto      ISRVECT

  ;; -------------------------------------
  ;; Bootloader (Subroutines)
uart_tx_byte
  btfss     PIR1,TXIF
  goto      uart_tx_byte
  movwf     TXREG
  return

  ;; -------------------------------------
  ;; Bootloader (init)
boot
  ;; bank 3
  bsf       STATUS,RP0
  bsf       STATUS,RP1
  ;; movlw     b'00001000'		; TX non-inverted, 16bit Baudrate, no auto baud detect
  movlw     b'00011000'		; TX inverted, 16bit Baudrate, no auto baud detect
  movwf     BAUDCTL

  ;; bank 1
  bcf       STATUS,RP1
  movlw     b'00100100'         ; Baudrate = High Speed, async mode, transmit enabled, 8bit
  movwf     TXSTA
  movlw     .34               	; Baudrate = 57600 (@ 8MHz) -> -0,79 % Error
  ;; movlw     .51               	; Baudrate = 38400 (@ 8MHz) -> -0,002 % Error
  ;; movlw     .103               	; Baudrate = 19200 (@ 8MHz) ->  0,16 % Error
  movwf     SPBRG
  clrf      SPBRGH

  ;; bank 0
  bcf       STATUS,RP0
  movlw     b'10010000'		; enable Serial Port, 8bit, enable continues receive, disable address detection
  movwf     RCSTA


wait_cmd
  btfsc     PIR1,RCIF
  goto      uart_rx_byte
  btfss     RCSTA,OERR
  goto      uart_rx_oe
  goto      wait_cmd

uart_rx_oe
  bcf       RCSTA,CREN
  bsf       RCSTA,CREN
  goto      wait_cmd

uart_rx_byte
  btfsc     RCSTA,FERR
  goto      uart_rx_fe
  movf      RCREG,w             ; TODO: check parity??
  movwf     TMP			; TODO: move to input string
	;; TODO: check if command is finished and jump
	;;       to 'exec_cmd'
  return

uart_rx_fe
  movf      RCREG,w
  goto      wait_cmd

exec_cmd
	;; TODO: execute received command
  goto      USERVECT

  ;; -------------------------------------
  ;; dummy user code
  org       USERVECT
  goto      USERVECT

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