W78E516B
Application Note: In-system Programming Software Examples
This application note illustrates the in-system programmability of the Winbond W78E516B MTP-ROM
microcontroller. In this example, microcontroller will boot from 64 KB APROM bank and waiting for a
key to enter in-system programming mode for re-programming the contents of 64 KB APROM. While
entering in-system programming mode, microcontroller executes the loader program in 4KB LDROM
bank. The loader program erases the 64 KB APROM then reads the new code data from external
SRAM buffer (or through other interfaces) to update the 64KB APROM.
EXAMPLE 1:
;*******************************************************************************************************************
;* Example of 64K APROM program: Program will scan the P1.0. if P1.0 = 0, enters in-system
;* programming mode for updating the content of APROM code else executes the current ROM code.
;* XTAL = 40 MHz
;*******************************************************************************************************************
.chip 8052
.RAMCHK OFF
.symbols
CHPCON EQU
CHPENR EQU
BFH
F6H
C4H
SFRAL
SFRAH
SFRFD
SFRCN
EQU
EQU C5H
EQU
EQU
C6H
C7H
ORG 0H
LJMP 100H
; JUMP TO MAIN PROGRAM
;************************************************************************
;* TIMER0 SERVICE VECTOR ORG = 000BH
;************************************************************************
ORG 00BH
CLR
TR0
; TR0 = 0, STOP TIMER0
MOV TL0,R6
MOV TH0,R7
RETI
;************************************************************************
;* 64K APROM MAIN PROGRAM
;************************************************************************
ORG 100H
MAIN_64K:
MOV A,P1
; SCAN P1.0
ANL A,#01H
CJNE A,#01H,PROGRAM_64K ; IF P1.0 = 0, ENTER IN-SYSTEM PROGRAMMING MODE
JMP NORMAL_MODE
PROGRAM_64K:
MOV CHPENR,#87H
; CHPENR = 87H, CHPCON REGISTER WRTE ENABLE
; CHPENR = 59H, CHPCON REGISTER WRITE ENABLE
; CHPCON = 03H, ENTER IN-SYSTEM PROGRAMMING MODE
; TR = 0 TIMER0 STOP
MOV CHPENR,#59H
MOV CHPCON,#03H
MOV TCON,#00H
MOV IP,#00H
; IP = 00H
MOV IE,#82H
MOV R6,#FEH
; TIMER0 INTERRUPT ENABLE FOR WAKE-UP FROM IDLE MODE
; TL0 = FEH
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