radix DEC
	LIST      P=18F46K22	; change also: Configure->SelectDevice from Mplab 
xtal EQU 16000000		; you may want to change: _XT_OSC_1H  _HS_OSC_1H  _HSPLL_OSC_1H
baud EQU 57600			; the desired baud rate
delaytime EQU 2000000   ; for 40MHz: 1000000 gets about 1sec, for 20MHZ: 2000000 gets about 1sec
	; The above 4 lines can be changed and buid a bootloader for the desired frequency (and PIC type)
	
	;********************************************************************
	;	Tiny Bootloader		18F series		Size=100words
	;	claudiu.chiculita@ugal.ro
	;	http://www.etc.ugal.ro/cchiculita/software/picbootloader.htm
	;********************************************************************
	

	#include "../icdpictypes.inc"	;takes care of: #include "p18fxxx.inc",  max_flash, IdTypePIC
	#include "../spbrgselect.inc"	; RoundResult and baud_rate

		#define first_address max_flash-200		;107 words
	
	;can we dump these ? winpic etc have the function of configuring all
	__CONFIG _CONFIG1H, H'08'
	__CONFIG _CONFIG2L, H'00' 
	__CONFIG _CONFIG2H, H'3E'
	__CONFIG _CONFIG3H, H'A0'
	__CONFIG _CONFIG4L, H'81'
	__CONFIG _CONFIG5L, H'0F'
	__CONFIG _CONFIG5H, H'C0' 
	__CONFIG _CONFIG6L, H'0F'
	__CONFIG _CONFIG6H, H'E0'
	__CONFIG _CONFIG7L, H'0F'
	__CONFIG _CONFIG7H, H'40'


;----------------------------- PROGRAM ---------------------------------
	cblock 0
	crc
	i
	cnt1
	cnt2
	cnt3
	counter_hi
	counter_lo
	flag
	endc
	cblock 10
	buffer:64
	endc
	
SendL macro car
	movlw car
	movwf TXREG
	endm
	
;0000000000000000000000000 RESET 00000000000000000000000000

		ORG     0x0000
		GOTO    IntrareBootloader

;view with TabSize=4
;&&&&&&&&&&&&&&&&&&&&&&&   START     &&&&&&&&&&&&&&&&&&&&&&
;----------------------  Bootloader  ----------------------
;PC_flash:		C1h				U		H		L		x  ...  <64 bytes>   ...  crc	
;PC_eeprom:		C1h			   	40h   EEADR   EEDATA	0		crc					
;PC_cfg			C1h			U OR 80h	H		L		1		byte	crc
;PIC_response:	   type `K`
	
	ORG first_address		;space to deposit first 4 instr. of user prog.
	nop
	nop
	nop
	nop
	org first_address+8
IntrareBootloader
    setf  OSCCON		;16 MHz HFintosc
    movlb 0x0F			;switch off analog feature on PortC
    clrf  0x3A,1
    movlw b'10000101'   ;setup tmr0
    movwf T0CON

						;init serial port 
	movlw b'00100100'
	movwf TXSTA
    movlw b'10010000'
	movwf RCSTA
    bsf   BAUDCON, BRG16  
    clrf  SPBRGH
	movlw 0x44
	movwf SPBRG

							;wait for computer
	rcall Receive			
	sublw 0xC1				;Expect C1h
	bnz way_to_exit
	SendL IdTypePIC			;send PIC type
MainLoop
	SendL 'K'				; "-Everything OK, ready and waiting."
mainl
	clrf crc
	rcall Receive			;Upper
	movwf TBLPTRU
		movwf flag			;(for EEPROM and CFG cases)
	rcall Receive			;Hi
	movwf TBLPTRH
		movwf EEADR			;(for EEPROM case)
	rcall Receive			;Lo
	movwf TBLPTRL
		movwf EEDATA		;(for EEPROM case)

	rcall Receive			;count
	movwf i
	incf i
	lfsr FSR0, (buffer-1)
rcvoct						;read 64+1 bytes
		movwf TABLAT		;prepare for cfg; => store byte before crc
	rcall Receive
	movwf PREINC0
	decfsz i
	bra rcvoct
	
	tstfsz crc				;check crc
	bra ziieroare
		btfss flag,6		;is EEPROM data?
		bra noeeprom
		movlw b'00000100'	;Setup eeprom
		rcall Write
		bra waitwre
noeeprom
		btfss flag,7		;is CFG data?
		bra noconfig
		tblwt*				;write TABLAT(byte before crc) to TBLPTR***
		movlw b'11000100'	;Setup cfg
		rcall Write
		bra waitwre
noconfig
							;write
eraseloop
	movlw	b'10010100'		; Setup erase
	rcall Write
	TBLRD*-					; point to adr-1
	
writebigloop	
	movlw 8					; 8groups
	movwf counter_hi
	lfsr FSR0,buffer
writesloop
	movlw 8					; 8bytes = 4instr
	movwf counter_lo
writebyte
	movf POSTINC0,w			; put 1 byte
	movwf TABLAT
	tblwt+*
	decfsz counter_lo
	bra writebyte
	
	movlw	b'10000100'		; Setup writes
	rcall Write
	decfsz counter_hi
	bra writesloop
waitwre	
;	btfsc EECON1,WR		;for eeprom writes (wait to finish write)
;	bra waitwre			;no need: round trip time with PC bigger than 4ms
	
	bcf EECON1,WREN			;disable writes
	bra MainLoop
	
ziieroare					;CRC failed
	SendL 'N'
	bra mainl
	  
;******** procedures ******************

Write
	movwf EECON1
	movlw 0x55
	movwf EECON2
	movlw 0xAA
	movwf EECON2
	bsf EECON1,WR			;WRITE
	nop
	;nop
	return


Receive
    clrf  TMR0H				;use timer0 insted of simple counter !!! commented lines are original source
    clrf  TMR0L
    bcf   INTCON,T0IF
;	movlw xtal/delaytime+1	; for 20MHz => 11 => 1second delay
;	movwf cnt1
;rpt2						
;	clrf cnt2
;rpt3
;	clrf cnt3
rptc
		btfss PIR1, RCIF			;test RX
		bra notrcv
	    movf RCREG,w			;return read data in W
        addwf crc,f				;compute crc
 		return
notrcv
;	decfsz cnt3
;	bra rptc
;	decfsz cnt2
;	bra rpt3
;	decfsz cnt1
;	bra rpt2
    btfss INTCON,T0IF
    bra rptc
	;timeout:
way_to_exit
	bcf	RCSTA,	SPEN			; deactivate UART
	bra first_address
;*************************************************************
; After reset
; Do not expect the memory to be zero,
; Do not expect registers to be initialised like in catalog.


 END