slfprg-s08aw.asm

M68HC08 及HCS08系列单片机bootloader引导程序源码、示例

    		ORA		  #mFSTAT_FACCERR				                
    		STA	  	FSTAT					; clear any FACCERR flag

	  IFNDEF HISPEED
        LDA	  	#%00001101				; div by 13 to fit into 150-200kHz Flash clock!
	  ELSE
        LDA	  	#36					    	; div by 36+1 to fit into 150-200kHz Flash clock!
	  ENDIF
        STA		  FCDIV
        
        BSET    TXDBIT,TXDPORT
        BSET    TXDBIT,TXDDDR           ; TxD high when SCI disabled        

        MOV     #%00001100,SCC2  		; transmit & receive enable
    		CLR	  	SCIBDH

	  IFNDEF HISPEED
    		MOV	  	#16, SCIBDL				; BUS (2.4576M)/(16 * 16) = 9600Bd
	  ELSE
    		MOV	  	#4, SCIBDL				; BUS (7.3728M)/(16 * 4) = 115200Bd
	  ENDIF
      	CLR     SCC3

      	LDA	    SCS1
      	MOV	    #ACK,SCDR

      	LDX	    #T100MS
L2:	    CLRA
L1:	    BRSET	  RDRF,SCS1,CAUGHT
      	DBNZA 	L1
      	DBNZX   L2
ILOP:
;       timeout
        ILOP          ; generate RESET by doing illegal operation
;*******************************************************************************************
CAUGHT:			; CAUGHT IN SELF-PROGRAMMING?
      	BSR     READ
        CLR     SCC2			      ; disable SCI
        JSR     ICGTRIM		      ; go & trim
        MOV     #%00001100,SCC2 ; transmit & receive enable

;*******************************************************************************************
; successful return from all write routines
SUCC:
        LDA     #ACK
      	BSR     WRITE

;fall thru to background
;*******************************************************************************************
; BEGIN OF BACKGROUND COMMAND LOOP
BCKGND:
      	BSR     READ
            
        CBEQA   #ERASE, ERASE_COM       ; Erase command
        CBEQA   #WR_DATA, WR_DATA_COM   ; Write (program) command
        CBEQA   #IDENT, IDENT_COM       ; Ident command
      IF RCS_ENA = 1
        CBEQA   #RD_DATA, RD_DATA_COM   ; Read command
      ENDIF

        ; if no valid command found (including Quit)
        ; generate reset too!
        ILOP          ; generate RESET by doing illegal operation
        
;*******************************************************************************************
IDENT_COM:                      ; TRANSFER OF IDENTIFICATION STRING
        LDA     #(VER_NUM | RCS)  ; version number & "Read command supported" flag
    		BSR	  	WRITE
    		LDA		  SDIDH			; system device identification 1 register (high)
    		BSR	  	WRITE
    		LDA	  	SDIDL			; system device identification 1 register (low)
    		BSR	  	WRITE

        MOV     #ID_STRING_END-ID_STRING, LEN
    		LDHX  	#ID_STRING
        BSR     WRITE_LOOP
                 
        BRA     BCKGND          ; finish without ACK
;*******************************************************************************************
WRITE_LOOP:             ; start address in HX, length in LEN
      	LDA	    ,X
        BSR	    WRITE
      	AIX	    #1
        DBNZ    LEN, WRITE_LOOP
        RTS
;*******************************************************************************************
      IF RCS_ENA = 1
RD_DATA_COM:

      	BSR     READ
      	STA	    ADRS
      	BSR     READ
      	STA	    ADRS+1
      	BSR     READ
      	STA	    LEN
      	LDHX	  ADRS
        
        BSR     WRITE_LOOP

        BRA     BCKGND          ; finish without ACK
      ENDIF

;*******************************************************************************************
WRITE:	
        BRCLR	  TC,SCS1,WRITE
      	STA	    SCDR
      	RTS
READ:
        BRCLR 	RDRF,SCS1,READ
      	LDA	    SCDR
      	RTS

;*******************************************************************************************
ERASE_COM:
      	BSR     READ
      	STA	    ADRS
      	BSR     READ
      	STA	    ADRS+1

    		lda   	#(mFSTAT_FPVIOL+mFSTAT_FACCERR) ;mask
    		sta   	FSTAT 				;abort any command and clear errors

    		mov	  	#EraseSubSize, STAT	;length of flash erase routine to STAT
    		tsx
    		sthx  	STACK
    		ldhx  	#EraseSubEnd-1 		;point at last byte to move to stack

    		bra   	DoOnStack 			;execute prog code from stack RAM
;*******************************************************************************************
WR_DATA_COM:
      	BSR     READ
      	STA	    ADRS
      	BSR     READ
      	STA	    ADRS+1
      	BSR     READ
      	STA	    STAT
        STA     LEN
        LDHX    #DATA
        STHX	  ADRR
WR_DATA_L1:
      	BSR     READ
        STA     ,X
        AIX     #1
        DBNZ    STAT,WR_DATA_L1
		
    		lda   	#(mFSTAT_FPVIOL+mFSTAT_FACCERR) ;mask
    		sta   	FSTAT 				;abort any command and clear errors

    		mov	  	#ProgSubSize, STAT	;length of flash prog routine to STAT
    		tsx
    		sthx	  STACK
    		ldhx 	  #ProgSubEnd-1		;point at last byte to move to stack

;		bra 	DoOnStack 			;execute prog code from stack RAM
		; fallthru to this routine
;*******************************************************************************************
DoOnStack: 
    		lda 	  ,x 				;read from flash
    		psha 					;move onto stack
    		aix 	  #-1 			;next byte to move
    		dbnz	  STAT, DoOnStack
    		tsx 					;point to sub on stack
    		jmp 	  ,x 				;execute the sub on the stack (will return on it's own)		
;*******************************************************************************************
EraseSub: 	
    		ldhx  	ADRS		 	;get flash address
    		sta   	0,x 			;write to flash; latch addr and data
    		lda   	#mPageErase 	;get flash command
    		sta   	FCMD 			;write the flash command
    		lda   	#mFSTAT_FCBEF 		;mask to initiate command
    		sta   	FSTAT 			;[pwpp] register command
    		nop 					;[p] want min 4~ from w cycle to r
ChkDoneErase: 
    		lda   	FSTAT 			;[prpp] so FCCF is valid
    		lsla 					;FCCF now in MSB
    		bpl   	ChkDoneErase 	;loop if FCCF = 0

    		ldhx	  STACK
    		txs
        jmp     SUCC		    ;refer status back to PC
EraseSubEnd: 
EraseSubSize: equ (*-EraseSub)
;*******************************************************************************************
ProgSub: 	
    		lda   	FSTAT 			;check FCBEF
    		and   	#mFSTAT_FCBEF		;mask it
    		beq	  	ProgSub			;loop if not empty
    		
    		ldhx	  ADRR
    		lda	  	0,x
    		aix	  	#1
    		sthx  	ADRR
    		
    		ldhx 	  ADRS		 	;get flash address
    		sta   	0,x 			;write to flash; latch addr and data
    		aix	  	#1
    		sthx	  ADRS
    		
    		lda     #mBurstProg 	;get flash command
    		sta   	FCMD 			;write the flash command
    		lda   	#mFSTAT_FCBEF 		;mask to initiate command
    		sta   	FSTAT 			;[pwpp] register command
    		dbnz  	LEN,ProgSub		;all bytes in a row?
ChkDoneProg: 
    		lda   	FSTAT 			;[prpp] so FCCF is valid
    		lsla 					;FCCF now in MSB
    		bpl   	ChkDoneProg 	;loop if FCCF = 0
    		
    		ldhx	  STACK
    		txs
        jmp     SUCC	    	;refer status back to PC
ProgSubEnd: 
ProgSubSize: equ (*-ProgSub)
;*******************************************************************************************
ICGTRIM:
        CLRX
        CLRH
MONRXD:
        BRSET   RXDBIT,RXDPORT,MONRXD    ; WAIT FOR BREAK SIGNAL TO START
CHKRXD:
        BRSET   RXDBIT,RXDPORT,BRKDONE   ; (5) GET OUT OF LOOP IF BREAK IS OVER
        AIX     #1              ; (2) INCREMENT THE COUNTER
        BRA     CHKRXD          ; (3) GO BACK AND CHECK SIGNAL AGAIN
BRKDONE:
        PSHH
        PULA                    ; PUT HIGH BYTE IN ACC AND WORK WITH A:X

	  IFDEF HISPEED
    		LSLA
    		ROLX
    		LSLA
    		ROLX	; mul by 4 since we're 4 times slower
	  ENDIF

        TSTA                    ; IF MSB OF LOOP CYCLES = 0, THEN BREAK TAKES TOO
        TXA                     ; FEW CYCLES THAN EXPECTED, SO TRIM BY SPEEDING
        BEQ     SLOW            ; UP f OP .
FAST:   CMP     #$40            ; SEE IF BREAK IS WITHIN TOLERANCE
        BGE     OOR             ; DON'T TRIM IF OUT OF RANGE
        ASLA                    ; multiply by two to get right range
        ADD     #$80            ; BREAK LONGER THAN EXPECTED, SO SLOW DOWN f OP
        BRA     ICGDONE
SLOW:   CMP     #$C0            ; SEE IF BREAK IS WITHIN TOLERANCE
        BLT     OOR             ; DON'T TRIM IF OUT OF RANGE
        ASLA                    ; multiply by two to get right range
        SUB     #$80
ICGDONE:
        STA     ICGTRM
OOR:
        RTS
;*******************************************************************************************
END