
P89V52X2_3
NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 03 — 4 May 2009
38 of 57
NXP Semiconductors
P89V52X2
80C51 with 256 B RAM, 192 B data EEPROM
LOAD
EQU
00H
EP
EQU
68H
PGM_USER:
MOV
FMCON,#LOAD
;load command, clears page register
MOV
FMADRH,R4
;get high address
MOV
FMADRL,R5
;get low address
MOV
A,R7
;
MOV
R0,A
;get pointer into R0
LOAD_PAGE:
MOV
FMDAT,@R0
;write data to page register
INC
R0
;point to next byte
DJNZ
R3,LOAD_PAGE
;do until count is zero
MOV
FMCON,#EP
;else erase & program the page
MOV
R7,FMCON
;copy status for return
MOV
A,R7
;read status
ANL
A,#0FH
;save only four lower bits
JNZ
BAD
;
CLR
C
;clear error flag if good
RET
;and return
BAD:
SETB
C
;set error flag
RET
;and return
A C-language routine to load the page register and perform an erase/program operation is
shown below. This code assumes the data EEPROM has been mapped into user code
space.
#include <REGV52.H>
unsigned char idata dbytes[64];// data buffer
unsigned char Fm_stat;// status result
bit PGM_USER (unsigned char, unsigned char);
bit prog_fail;
void main ()
{
prog_fail=PGM_USER(0x1F,0xC0);
}
bit PGM_USER (unsigned char page_hi, unsigned char page_lo)
{
#define LOAD0x00// clear page register, enable loading
#define EP0x68// erase & program page
unsigned char i;// loop count
FMCON = LOAD;//load command, clears page reg
FMADRH = page_hi;//
FMADRL = page_lo;//write my page address to addr regs
for(i=0;i<64;i=i+1)
{