Discussion in "Project Help" started by    navintiwari08    Apr 12, 2012.
Thu Apr 12 2012, 07:10 PM
#1
hello everyone..
am having problem in writing and reading data from serial eeprom 24c02 interfaced with 8051(P89V51RD2).. please have a look at my program and help me out..
thanks a bunch:)

;-------------------------------------------
; using atmel 24c02 serial eeprom with 8051
;-------------------------------------------
sda equ p2.0
scl equ p2.1

org 00h
sjmp main

org 30h
main:

lcall eeprom_write
lcall eeprom_read
here:
sjmp here


eeprom_start:
setb sda
setb scl
lcall delay
clr sda
lcall delay
clr scl
ret

eeprom_stop:
clr sda
setb scl
lcall delay
setb sda
lcall delay
clr scl
ret

eeprom_write:
lcall eeprom_start
mov a,#0a0h ;device address with write bit
lcall send_data
mov a,#00h ;memory address on device to write to
lcall send_data
mov a,#25h ;data to write on the eeprom
lcall send_data
lcall eeprom_stop
ret

eeprom_read:
lcall eeprom_start
mov a,#0a0h ;device address with write bit(to perform dummy write)
lcall send_data
mov a,#00h ;memory address on device to set the address pointer
lcall send_data
lcall eeprom_start ;repeated start
mov a,#0a1h ;device address with read bit
lcall send_data
lcall get_data ;start reading
lcall eeprom_stop
ret

send_data:
mov r0,#08
loop: clr scl
lcall delay
rlc a
mov sda,c
lcall delay
setb scl
lcall delay
clr scl
djnz r0,loop
setb sda
ack: jb sda,ack ;polling the acknowledge by the device
setb scl
lcall delay
clr scl
ret

get_data:
mov r0,#08
setb sda
nop
loop1:
mov c,sda
setb scl
nop
nop
clr scl
rlc a
djnz r0,loop1
mov p0,a
ret

delay: mov r1,#10
rep: djnz r1,rep
ret

end


[ Edited Thu Apr 12 2012, 07:18 PM ]
Sat Apr 14 2012, 03:01 AM
#2
you have to put delay of atleast 5 to 10 ms after eeprom write to complete the write cycle. I am assuming your I2C is working fine.
Sat Apr 14 2012, 08:28 AM
#3
hello Ajay.. thanx for the reply.. i tried giving it the delay u proposed but it is still not working.. is my program correct? i checked many times but cant spot the error.. pls help. thanks..
Sun Apr 15 2012, 04:43 AM
#4
I dont see any problem the way you are reading from EEPROM but as I said, I am assuming your I2C driver is correct and working fine. You can take i2c reference from tutorial section. and see if everything is alright.
Sun Apr 15 2012, 08:23 AM
#5
thanks a lot Ajay, for the help.. i just solved it.. the 24c02a IC was damaged. i think i burnt it up.. i got a new 24c02 and its working perfectly.. thanks for caring to reply.. have a great day:)
Mon Apr 16 2012, 06:21 PM
#6
thats a good news. keep up the good work. Good Luck!

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ExperimenterUK
Mon May 25 2015, 06:21 PM
@Subrat Sahu not a simple answer.Create a thread in "General help Guidance and Discussion" forum
Sun May 24 2015, 06:51 AM
Subrat Sahu
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ExperimenterUK
Sat May 23 2015, 08:54 PM
@utpal.. Create a thread in the Pic forum
Thu May 21 2015, 01:04 AM
utpal
i am a hobbist. i work on 8051. just i have started with pic 16f877. but a bitter experiance is going on. as i am programming any code to my pic877 and putting it in my board and it is working, but the 2nd time it is not taking any program,I have experimented just 7 new one pic mcus. result is the same. please tell me the reason. my programmer is TOP3000(universal programmer).
ajay_bhargav
Wed May 20 2015, 04:48 AM
@lak you can use the same code provided you are not using any s52 specific ports and registers.
Mon May 18 2015, 05:58 AM
lak
i used to develop a code for at89s52 shall i use the same code for at89c4051
Sun May 17 2015, 07:57 AM
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what if i have to rotate motor continuously at a step angle of 1.8 degree
ExperimenterUK
Fri May 15 2015, 06:02 PM
@oracle1946.. Post your question in the PIC forum
Fri May 15 2015, 03:48 AM
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if some has solution kindly share solution Principles of Electric Circuits,by Thomas L. Floyd
oracle1946
Thu May 14 2015, 03:39 PM
I want to build a PIC16F684 sun logger using either a solar cell (0.5v solar cell or photoresistor). Any help out there?

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