Preliminary W78LE516
- 30 -
MOV A,SFRFD ; READ ONE BYTE
CJNE A,#FFH,BLANK_CHECK_ERROR
INC SFRAL ; NEXT ADDRESS
MOV A,SFRAL
JNZ BLANK_CHECK_LOOP
INC SFRAH
MOV A,SFRAH
CJNE A,#0H,BLANK_CHECK_LOOP ; END ADDRESS = FFFFH
JMP PROGRAM_64KROM
BLANK_CHECK_ERROR:
MOV P1,#F0H
MOV P3,#F0H
JMP $
;*******************************************************************************
;* RE-PROGRAMMING 64KB APROM BANK
;*******************************************************************************
PROGRAM_64KROM:
MOV DPTR,#0H ; THE ADDRESS OF NEW ROM CODE
MOV R2,#00H ; TARGET LOW BYTE ADDRESS
MOV R1,#00H ; TARGET HIGH BYTE ADDRESS
MOV DPTR,#0H ; EXTERNAL SRAM BUFFER ADDRESS
MOV SFRAH,R1 ; SFRAH, TARGET HIGH ADDRESS
MOV SFRCN,#21H ; SFRCN(C7H) = 21 (PROGRAM 64K)
MOV R6,#BEH ; SET TIMER FOR PROGRAMMING, ABOUT 50 µS.
MOV R7,#FFH
MOV TL0,R6
MOV TH0,R7
PROG_D_64K:
MOV SFRAL,R2 ; SFRAL(C4H) = LOW BYTE ADDRESS
MOVX A,@DPTR ; READ DATA FROM EXTERNAL SRAM BUFFER. BY ACCORDING USER?
; CIRCUIT, USER MUST MODIFY THIS INSTRUCTION TO FETCH CODE.
MOV SFRFD,A ; SFRFD(C6H) = DATA IN
MOV TCON,#10H ; TCON = 10H, TR0 = 1,GO
MOV PCON,#01H ; ENTER IDLE MODE (PRORGAMMING)
INC DPTR
INC R2
CJNE R2,#0H,PROG_D_64K
INC R1
MOV SFRAH,R1
CJNE R1,#0H,PROG_D_64K
;*****************************************************************************
; * VERIFY 64KB APROM BANK
;*****************************************************************************
MOV R4,#03H ; ERROR COUNTER
MOV R6,#FEH ; SET TIMER FOR READ VERIFY, ABOUT 1.5 µS.
MOV R7,#FFH
MOV TL0,R6
MOV TH0,R7
MOV DPTR,#0H ; The start address of sample code
MOV R2,#0H ; Target low byte address