Serial EEPROM 24AA256T-E/MNY I2C addres

Go To Last Post
3 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0


Hello,

can you please someone help me with following addressing issue of I2C EEPROM memory?

EEPROM 24AA256T has fixed address 1010 + A2 A1 A0 . We set up address to 1010100 = 0x54.

Unfortunately when I try address I2C slave devices from address 0x50 to 0x57 then this one memory send ACK for all to I2C master (MCU) - bellow you can see data from analyzer. I think only memory with valid I2C address (fixed part + address pins) can send ACK.. 

I2C bus speed 100kHz, Write protect enable. Please can you send me some advice, where can be problem? 

 

Thank you,

Jan

 

 

This topic has a solution.
Last Edited: Mon. Aug 1, 2022 - 03:48 PM
This reply has been marked as the solution. 
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Read the datasheet.   From the AT24C256 datasheet.  A2 is a dummy (NC).   Only A0, A1 can select the address.  e.g. 0x50, 0x51, 0x52, 0x53

 

I suspect that the Microchip 24AA256 will be the same.  (Untested)

 

David.

Last Edited: Sun. Jul 31, 2022 - 08:32 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0


Hello David,

thank you, you have right. We got from supplier other part number which should be compatible, but this address pin behaviour is different. Memory doesn't care about address pins.. So all addresses with prefix 1010xxx are valid.

Thank you and have a nice day,

Jan