Nuvoton NuMicro MS51PC0AE - Page 259

MS51
Nov. 28, 2019 Page 259 of 491 Rev 1.00
MS51 32K SERIES TECHNICAL REFERENCE MANUAL
supports IAP function and any byte in the Flash Memory array may be read using the MOVC
instruction and thus is suitable for use as non-volatile data storage. IAP provides erase and program
function that makes it easy for one or more bytes within a page to be erased and programmed in a
routine. IAP performs in the application under the control of the microcontroller’s firmware. Be aware
of Flash Memory writing endurance of 100,000 cycles. A demo is illustrated as follows.
Assembly
:
;**************************************************************************
****
; This code illustrates how to use IAP to make APROM 201h as a byte of
; Data Flash when user code is executed in APROM.
;**************************************************************************
****
PAGE_ERASE_AP EQU 00100010b
BYTE_PROGRAM_AP EQU 00100001b
ORG 0000h
MOV TA,#0Aah ;CHPCON is TA protected
MOV TA,#55h
ORL CHPCON,#00000001b ;IAPEN = 1, enable IAP mode
MOV TA,#0Aah ;IAPUEN is TA protected
MOV TA,#55h
ORL IAPUEN,#00000001b ;APUEN = 1, enable APROM update
MOV IAPCN,#PAGE_ERASE_AP ;Erase page 200h~27Fh
MOV IAPAH,#02h
MOV IAPAL,#00h
MOV IAPFD,#0FFh
MOV TA,#0Aah ;IAPTRG is TA protected
MOV TA,#55h
ORL IAPTRG,#00000001b ;write ‘1’ to IAPGO to trigger IAP
process
MOV IAPCN,#BYTE_PROGRAM_AP ;Program 201h with 55h
MOV IAPAH,#02h
MOV IAPAL,#01h
MOV IAPFD,#55h
MOV TA,#0Aah
MOV TA,#55h
ORL IAPTRG,#00000001b
MOV TA,#0Aah
MOV TA,#55h
ANL IAPUEN,#11111110b ;APUEN = 0, disable APROM update
MOV TA,#0Aah
MOV TA,#55h
ANL CHPCON,#11111110b ;IAPEN = 0, disable IAP mode
MOV DPTR,#201h