Assembly code for EEPROM 24c16


Sample code for EEPROM 24c16.
Following code can be using for 8051 and 8052 ICs like: 89c51, 89c52, 89s51, 89s52, 89c2051.
And with little bit modification, this assembly program can be used for: 24c02, 24c04, 24c08, 24c32 

 

;==========================================================
;	Pin Definations
;==========================================================
eeprom_scl_pin          equ     a4h	;scl p2.4
eeprom_sda_pin          equ     a5h	;sda p2.5
;==========================================================
; Main Program starts from here
;==========================================================
                mov memory_address1,#00h
                mov memory_address2,#00h
                mov eeprom_data,#05
                call write_data

                mov memory_address1,#00h
                mov memory_address2,#00h
                call read_data
                mov 5dh,3ch

loop            jmp loop
;=========================================================
; Sub routines starts from here
;=========================================================
write_data      call eeprom_start
                mov a,#a0h          
                call send_data
                mov a,memory_address1          ;location address
                call send_data
                mov a,memory_address2          ;location address
                call send_data
                mov a,eeprom_data              ;data to be send
                call send_data
                call eeprom_stop
                ret   
;=========================================================
read_data       call eeprom_start
                mov a,#a0h
                call send_data
                mov a,memory_address1          ;location address
                call send_data
                mov a,memory_address2          ;location address
                call send_data
                call eeprom_start
                mov a,#a1h
                call send_data
                call get_data
                call eeprom_stop
                ret
;=========================================================
eeprom_start    setb eeprom_sda_pin
                nop
                setb eeprom_scl_pin
                nop
                nop
                clr eeprom_sda_pin
                nop
                clr eeprom_scl_pin
                ret
;=========================================================
eeprom_stop     clr eeprom_sda_pin
                nop
                setb eeprom_scl_pin
                nop
                nop
                setb eeprom_sda_pin
                nop
                clr eeprom_scl_pin
                ret
;=========================================================
send_data      mov r7,#00h
send           rlc a
               mov eeprom_sda_pin,c
               call clock
               inc r7
               cjne r7,#08,send
               setb eeprom_sda_pin
               jb eeprom_sda_pin,$
             ; call eeprom_delay
               call clock
               ret
;=========================================================
get_data
               mov r7,#00h
               setb eeprom_sda_pin
get            mov c,eeprom_sda_pin
               call clock
               rlc a
               inc r7
               cjne r7,#08,get
               setb eeprom_sda_pin
               call clock
               mov 3ch,a
               ret
;=========================================================
clock          setb eeprom_scl_pin
               nop
               nop
               clr eeprom_scl_pin
               ret
;=========================================================
eeprom_delay       mov 33h,#11      ;delay of 3 msec 
eeprom_delay_1     mov 32h,#ffh
                   djnz 32h,$
                   djnz 33h,eeprom_delay_1
                   ret
;=====================================================
;      	Program ENDS here
;=====================================================