Discussion in "8051 Discussion Forum" started by    Abhinav    Jun 13, 2010.
Sun Jun 13 2010, 06:43 PM
Hi friends

i am a little confused while using AT24C04. like how many addresses are available for storing the data bytes?

The slave address is 1010 for all EEPROM'S so can we use 2 EEPROM's with one micro?

How to store values bigger that a byte in EEPROM?

i am using BASCOM for coding.

thank you all.
Sun Jun 13 2010, 07:57 PM
>The slave address is 1010 for all EEPROM'S so can we use 2 EEPROM's with one micro?
those are upper 4 bits of 7-bit address. the lower 3 bits are configurable which means yes you can use more than 1 rather total of 8 such EEPROMs at a time.

>How to store values bigger that a byte in EEPROM?
split them in 2 or 3 depending on how big your data is..
let say if its a 16-bit value then:
EEPROMWrite(Add, data>>8); // write first 8bits

sorry i am not good at bascom

before you calculate the size of sub address you need to know how much memory is addressable. lets take an example of 24C02 EEPROM.
24C02 is 2kbit = 2/8 kByte = 1/4Kb = 256bytes

so to accomodate 256 addresses you need 1 byte (00 to 255). so your sub address will only be of 1 byte.

now lets take case with 24C16
24C16 is 16Kbit = 16/8Kbyte = 2Kb = 2048 bytes
so we need atleast 2 bytes to accomodate 2048 addresses. so sub address now will be of 2 bytes in this case.

so you can see how we decide the internal data addresses of EEPROM.
Mon Jun 14 2010, 07:56 AM
Hi ajay

Thanks for a amazing detailed reply.

As per this website http://www.digchip.com/datasheets/parts/datasheet/054/AT24C04-10PC-1_8.php
we can connect maximum of-

AT24C01/02 = 8
AT24C04 = 4
AT24C08 = 2
AT24C16 = 1

because of their reducing hard wired addressing pins.

I cannot understand fully the meaning of below-

"AT24C04, 4K SERIAL EEPROM: Internally organized with 32 pages of 16 bytes each,
the 4K requires a 9-bit data word address for random word addressing"
as written in datasheet.

"The 4K is internally organized with 256 pages of 2-bytes each."
as described on digichip website.

thank you so much.

Mon Jun 14 2010, 02:25 PM
when addressing register there are two path, first on which page that register lies second what is the address of that register on that particular page.

you can assume MSB of address to be as page address and LSB as address of register on that page. so you can understand better what is page address and how it relates to register address.

even in 8051 we have page addressing of ram in which RAM is organized as 256 pages of 256 bytes each. so total accessible ram by 8051 is 256*256 = 65536 bytes. when interfacing external ram the page address is given by P2 and register address is given by P0. relate to it and you will understand.
Thu Jun 17 2010, 07:07 PM
hi ajay,

now i understood almost all things just one to ask that if start sending data bytes from address 0 then i think i have to send address(16) again after 16 bytes else first byte will be overwritten.

am i right ?

thanks
Thu Jun 17 2010, 07:20 PM
write operation will not work if you dont send a stop after page size limit of EEPROM.

You can see every EEPROM datasheet explains Page write operation differently from byte write operation. datasheet will provide you complete details.

### Information

#### Conversation

Sat Feb 01 2020, 10:12 AM
Pearl Olin
Hello,
Wed Jan 22 2020, 06:16 PM
MINU CHAUDHARY
I m getting errors while simulation process during interfacing socket output and lcd... Can i get the report of ur project which is same as us.
Tue Jan 14 2020, 07:08 AM
when i am trying to simulate the program in Proteus 8 professional, I am getting some errors as cannot find module file dhtxx.md can u help me
Tue Dec 17 2019, 01:44 PM
Devangi
hello..i am programming industrial timer using 8051 with 24lc64 eeprom. i have query in storing the 3 diff value in eeprom with enter button. can anyone share c code ?
Tue Dec 17 2019, 10:30 AM
Andrius
Hello. Can anyone share the code in Bascon and scheme in Proteus?
Thu Nov 21 2019, 12:30 PM
raj2555
how to interface 8051 microcontroller with NRF24L01+ module
Sat Oct 12 2019, 10:23 PM
Sat Oct 12 2019, 10:18 AM
i am doing a countdown timer with 8051 for my project, unfortunately our professor had to take a leave of absence before he could teach us most of it.. can someone explain the .asm code of it for me?
Mon Sep 23 2019, 07:37 AM
Nathaniel
I am doing a project for my schools wireless security system with cameras,sensors and spot lights using 8051 micro controller, could you help me out with the design and its source code.
Wed Sep 18 2019, 08:48 PM
Caryn Kover

### Recent

arun.sapro
Wed Feb 12 2020, 04:47 PM
prathmiyer
Tue Feb 11 2020, 11:12 AM
Just4Fun
Sat Feb 01 2020, 01:29 PM
Deepkumar
Thu Jan 30 2020, 03:52 PM
wounder
Sat Jan 25 2020, 12:09 PM
brucewilliams20
Thu Jan 23 2020, 11:47 AM
Nippy56
Sun Jan 19 2020, 02:13 AM
usb5962
Sat Jan 11 2020, 10:42 AM

#### Online

Guests: 107, Members: 0 ...

most ever online: 182184
(Members: , Guests: 182184) on 06 Aug 2010: 05:37 AM

Members: 38122
Forum Activity
##### Posted By wounder
Mon Feb 10 2020, 08:32 AM
From below sample code for nuvoton 8051 timer0 mod...
##### Posted By Just4Fun
Sat Feb 01 2020, 02:20 PM
If you want to use a CH55x MCU there isn't any adv...
##### Posted By Just4Fun
Sat Feb 01 2020, 01:51 PM
Hi all,I was curious to try out the CH552 MCU (805...
##### Posted By Deepkumar
Thu Jan 30 2020, 05:36 PM
I want to send a text message in other than the En...
##### Posted By ExperimenterUK
Sun Jan 26 2020, 04:05 AM
For a 12MHz crystal using a normal divided by 12 c...
##### Posted By wounder
Sat Jan 25 2020, 12:14 PM
I have a 8051 micro controller ,it has timer0,1,2,...
##### Posted By ExperimenterUK
Fri Jan 17 2020, 10:24 PM
We will need the circuit diagram.A Proteus simulat...
##### Posted By Billz
Sat Jan 11 2020, 05:43 PM
hi everyone please attached files are my c code fo...
##### Posted By ExperimenterUK
Tue Jan 07 2020, 08:18 PM
Not a stupid question.Setting up "Eclipse" can be...
##### Posted By elt
Tue Jan 07 2020, 07:06 PM
So i have just began learning programming micros a...