connetect two EEPROM with same address connect with i2c

[bagavathi]

Hi friends,

if we interface i2c with two eeprom with same slave address how to send data to the particular eeprom. this is interview question of my friend. answer?

 

[mathespbe]

Hi friends,

if we interface i2c with two eeprom with same slave address how to send data to the particular eeprom. this is interview question of my friend. answer?

you can use a 2x1 mux to enable sclk.... When SCLK available only the slave can be communicate right?

 

[spudboy488]

If you are "bit-banging" the I2C, send the SDA line to both and use separate SCL lines. If you are using hardware I2C, a simple MUX as described above will do. In either case, you'll need 3 I/O lines.

 

[embpic]

@mathespbe
is 2x1 mux will used to select the eeprom?
and clock which is input this is to send to output.But will it slow down the communication.

 

[betwixt]

You only switch the 1x2 MUX to select the appropriate device so it only takes one operation each time a selection is made, the I2C traffic isn't affected. I susect the real answer to the question is you select a different address using the hardwired address pins on the IC though, almost all, if not all, I2C devices have selectable address ranges.

Brian.

 

[mathespbe]

@mathespbe
is 2x1 mux will used to select the eeprom?
and clock which is input this is to send to output.But will it slow down the communication.

By means of a simple I/O line to the mux you can select the eeprom.
Since we are using a mux and we just need to select the eeprom from mux itself, this 'll be slower than using different slave addresses

 

[Raady Here]

Two EEPROMs cannot have same addresses as slave, it will create clash !

Two masters can send data to same slave addressed device with synchronization(MUX'ing) to save the page writes.

 

[Sneha Kunte.]

I guess using different slave addresses is more right way to do so. It can be done easily with hard-wired input pins.
Many EEPROM chips have this provision e.g. AT24C01A The device address word consists of a mandatory one, zero sequence for the first four
most significant bits. This is common to all the EEPROM devices. The next 3 bits are the A2, A1 and A0 device address bits for the 1K/2K EEPROM.
These 3 bits must compare to their corresponding hard-wired input pins.

 

[milind.a.kulkarni]

First of all it's better have different slave address on I2C I think mentioned by 'Sneha Kunte' but if there is any hard restriction like both of such device need to have same address then in such situation there is protocol similar to I2C is developed Called as SMBUS which having 3 pin called as Instruction( can be mostly treated as Chip Select ) can also be thought..... I am not sure dose your EPROM have such provision or not ..... but check SMBUS on wiki for an alternative.....

https://en.wikipedia.org/wiki/System_Management_Bus

also on the similar notes refer this chip which I2C EPROM + address control logic .... If you look a typical application of the chip you will get an idea how to use it in your situation and may help you -

**broken link removed**

Good Luck

 

[embpic]

if there is option for this problem then you can use other EEPROM which one having larger memory or one can use use different vendors and variety of EEPROM on same board.