Discussion in "8051 Discussion Forum" started by    Abhinav    Jun 13, 2010.
Sun Jun 13 2010, 06:43 PM
#1
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
#2
>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
EEPROMWrite(Add+1, data);//write next 8 bits to next address

sorry i am not good at bascom

and for your doubt regarding the subaddress/data address of EEPROM:
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.
Tags I2C eeprom addressingEEPROM interfacing 8051I2C EEPROM internal addressingi2c eeprom sub addressHow i2c eeprom addressing works
Mon Jun 14 2010, 07:56 AM
#3
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
#4
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
#5
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
#6
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.

Get Social

Information

Powered by e107 Forum System

Conversation

ExperimenterUK
Thu Nov 20 2014, 06:00 PM
@Mehboob.. I don't think you can do that.
Sat Nov 15 2014, 06:41 AM
Mehboob
Pls can you send me code in c of PWM generation using UART/serial port in 8051.
Fri Nov 14 2014, 02:51 PM
mohammad aqil
NEED A BOOK ON MICROPROCESSOR AND INTERFACING BY D.V.HALL. RIGHT NOW, I SHALL BE VERY THANK FULL TO U....
Thu Nov 13 2014, 02:15 PM
m
please code hex project avr blood pressure monitor
Thu Nov 13 2014, 05:56 AM
Lambo
hi mate, whats the ajay-bhargav? tell us more pls
ExperimenterUK
Wed Nov 12 2014, 12:56 AM
@tmtm000.. have you been able to join ?
ExperimenterUK
Wed Nov 12 2014, 12:54 AM
@Alice..become a member,then send a PM to ajay_bhargav the site owner.
Tue Nov 11 2014, 03:58 AM
Abhishek Bansal
Thanks a lot for your informative tutorials!
Mon Nov 10 2014, 09:03 AM
Alice
Hello, This is Alice from a PCB rototype manufacturer. Our company is interested in your website contents, and wonder if we can advertise our company with payment on your website. There are two ways to advertise: first, if we an get a instant quote section on your main site columns; second, whether we can get a advertising section if you have any avaliable one. If any of above ways avaliable, please contact me with your detailed scheme and advertising charge. Thanks. Alice
Sat Nov 08 2014, 11:58 AM
Mohamed_123sd
Signals and Systems, 2nd Edition by Alan V. Oppenheim Alan S.willsky with S.Hamid Nawab?

Downloads

Comments

PsySc0rpi0n
Thu Nov 27 2014, 02:00 PM
hanifnoor
Thu Nov 27 2014, 09:42 AM
dpkraju
Wed Nov 26 2014, 02:18 PM
sankalp_s
Tue Nov 25 2014, 05:13 PM
dodul
Mon Nov 24 2014, 10:08 PM
VikiPeter
Tue Nov 18 2014, 09:13 AM
gentlboy
Sun Nov 16 2014, 11:13 PM
philipeastbourne
Wed Nov 12 2014, 05:32 AM

Online

Guests: 54, Members: 0 ...

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

Members: 37552
Newest member: PsySc0rpi0n
Forum Activity
PsySc0rpi0n Avatar
Posted By PsySc0rpi0n
Thu Nov 27 2014, 02:30 PM
Hi...I'm new in forum and with programming 8051 co...
hanifnoor Avatar
Posted By hanifnoor
Thu Nov 27 2014, 09:45 AM
while(msg_array[i]!='\0') { if(msg_array[i]=...
rearthur2003 Avatar
Posted By rearthur2003
Thu Nov 27 2014, 05:23 AM
there are two types of diodes ir rx which is coat...
rearthur2003 Avatar
Posted By rearthur2003
Thu Nov 27 2014, 05:19 AM
First you will need to let us know what IDE you pl...
engr1931 Avatar
Posted By engr1931
Thu Nov 27 2014, 05:18 AM
yes sir! i only know assembly, and still in proces...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Nov 26 2014, 06:36 PM
I never tried sending SMS messages at a high rate,...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Nov 26 2014, 06:23 PM
connected my modem with Laptop via serial2usb cabl...
dodul Avatar
Posted By dodul
Wed Nov 26 2014, 04:30 PM
Hi,Thanks a lot for your reply. Yes i was referrin...
nomi77 Avatar
Posted By nomi77
Wed Nov 26 2014, 07:30 AM
@ajayAnother option is this if i can do void stor...
nomi77 Avatar
Posted By nomi77
Wed Nov 26 2014, 07:05 AM
@ajayI did same procedureconnected my modem with L...