boot2.asm

Mega8完美下载 包含源程序

; 读program memory
;****************************************************
L38:            cpi     R16,'R'                         ; else if(R16=='R') Read program memory
                brne    L40

                movw    R30,R26                         ; Z-pointer <= address

                lpm     R24,Z+                          ; read program memory LSB; store LSB in R24 and Z pointer ++
                lpm     R16,Z+                          ; read program memory MSB; store MSB in R16 and Z pointer ++
                rcall   uartSend                        ; uartSend(R16) MSB

                movw    R26,R30                         ; address += 2
                mov     R16,R24                         ; LSB stored in R16
                rjmp    L70                             ; uartSend(R16) LSB

;****************************************************
; 写EEPROM
;****************************************************
L40:            cpi     R16,'D'                         ; else if (R16=='D') Write data to EEPROM
                brne    L42

                rcall   uartGet
                out     EEDR,R16                        ; EEDR = uartGet()

                ldi     R17,6                           ; write EEPROM
                rcall   EepromTalk
                rjmp    Send_CR                         ; uartSend('\r')

;****************************************************
; 读EEPROM
;****************************************************
L42:            cpi     R16,'d'                         ; else if (R16=='d') Read data from EEPROM
                brne    L44

                ldi     R17,1                           ; read EEPROM
                rcall   EepromTalk                      ; R16 = EEPROM data
                rjmp    L70                             ; uartSend(R16)

;****************************************************
; 读熔断位和锁定位
;****************************************************
L44:            cpi     R16,'F'                         ; else if(R16=='F') Read fuse bits
                brne    L46

                clr     R30                             ; Z-pointer = 0000
                rjmp    L50                             ; rcall readFuseAndLock

;****************************************************
; 读锁定位
;****************************************************
L46:            cpi     R16,'r'                         ; else if(R16=='r') Read lock bits
                brne    L48

                ldi     R30,1                           ; Z pointer = 0001
                rjmp    L50                             ; rcall readFuseAndLock

;****************************************************
; 读熔断位高位
;****************************************************
L48:            cpi     R16,'N'                         ; else if(R16=='N') Read high fuse bits
                brne    L52
                ldi     R30,3                           ; Z-pointer = 0003

;****************************************************
; 读熔断位和锁定位
;****************************************************
L50:            rcall   readFuseAndLock
                rjmp    L70                             ; uartSend(R16)

;****************************************************
; 返回支持的芯片
;****************************************************
L52:            cpi     R16,'t'                         ; else if(R16=='t') Return supported devices code
                brne    L54

                ldi     R16,DT                          ; Device Type
                rcall   uartSend                        ; uartSend(DT) send Device Type

                clr     R16
                rjmp    L70                             ; uartSend(0)

;---  grab another char and ignore
L54:                                            ; else if ((R16=='l')||(R16=='x')||(R16=='y')||(R16=='T'))
                cpi     R16,'l'                         ; 'l' = Write Boot Loader lockbits 
                breq    L56
                cpi     R16,'x'                         ; 'x' = Set LED
                breq    L56
                cpi     R16,'y'                         ; 'y' = Clear LED
                breq    L56

                cpi     R16,'T'                         ; 'T' = Select device type
                brne    L60


L56:            rcall   uartGet                         ; R16 = uartGet()
; YOU CAN INSERT LEDs CODE HERE
                rjmp    Send_CR                         ; uartSend('\r')

;********************************************************
;* 返回一个7字节ASCII字符串说明编程器类型，我的为"AVRZLM8"  :)    
;********************************************************
L60:            cpi     R16,'S'                         ; else if (R16=='S') Return software identifier
                brne    L62

Boot_ID:        ldi     R30,low(2*Soft_ID)
                ldi     R31,high(2*Soft_ID)
L61:            lpm     R16,Z+
                tst     R16
                breq    L72                             ; branch is end of string ((Z) == 0)
                rcall   uartSend                        ; else send char
                rjmp    L61

;****************************************************
;*  发送两个字节的版本信息   
;****************************************************
L62:            cpi     R16,'V'                         ; else if (R16=='V') Return Software Version
                brne    L64

                ldi     R16,'1'                         ; uartSend('1')
                rcall   uartSend
                ldi     R16,'3'                         ; uartSend('2')
                rjmp    L70                             ; uartSend(R16)

;****************************************************
;* 发送电子标签    
;****************************************************
L64:            cpi     R16,'s'                         ; else if (R16=='s') Return Signature Byte
                brne    L66

                ldi     R16,SB1                         ; uartSend(SB1) Signature Byte 1
                rcall   uartSend
                ldi     R16,SB2                         ; uartSend(SB2) Signature Byte 2
                rcall   uartSend
                ldi     R16,SB3                         ; uartSend(SB3) Signature Byte 3
                rjmp    L70                             ; uartSend(R16)

L66:            ldi     R16,'?'                         ; else uartSend('?')
                rjmp    L70                             ; uartSend(R16)

;****************************************************
;* 发送一个“回车”字符（CR）    
;****************************************************
Send_CR:        ldi     R16,13                          ; uartSend('\r')

;****************************************************
;* 发送一个Ascii字符    
;****************************************************
L70:            rcall   uartSend                        ; uartSend(R16)
L72:            rjmp    Boot_Main

readFuseAndLock:
                clr     R31                             ; Z pointer high byte = 0
                ldi     R24,9                           ; SPMCR = 0x09
                out     SPMCR,R24                       ; read fuse and lock
                lpm     R16,Z                           ; read program memory
                ret

EepromTalk:                                             ; if R17 == 6 then Write, if R17 == 1 then Read
                out     EEARL,R26                       ; EEARL = address low
                out     EEARH,R27                       ; EEARH = address high
                adiw    R26,1                           ; address++
                sbrc    R17,1                           ; skip if R17 == 1 (read Eeprom)
                sbi     EECR,EEMWE                      ; EEMWE = 1 (write Eeprom)
                out     EECR,R17                        ; EECR = R17 (6 write, 1 read)
L90:            sbic    EECR,EEWE                       ; wait until EEWE == 0
                rjmp    L90
                in      R16,EEDR                        ; R16 = EEDR
                ret

uartSend:                                               ; send R16
                sbis    UCSRA,UDRE                      ; wait for empty transmit buffer (until UDRE==1)
                rjmp    uartSend
                out     UDR,R16                         ; UDR = R16, start transmission
                ret

uartGet:        sbis    UCSRA,RXC                       ; wait for incoming data (until RXC==1)
                rjmp    uartGet
                in      R16,UDR                         ; return received data in R16
                ret

;****************************************************
;* 关键是这个子程序！！
;*    Design Note #032上的程序，是为写的，在上不能正常运行。
;*    主要问题是在页写和擦除以后，不能再重新访问RWW。
;*    现在以改正这个bug!  
;****************************************************
wait_spm:       in      R16,SPMCR
                sbrc    R16,SPMEN
                rjmp    wait_spm
                ldi     R16,(1<<RWWSRE) | (1<<SPMEN)
                out     SPMCR,R16
                spm
                ret 

Soft_ID: .DB "AVRZLM8", 0