Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

[SOLVED] I2C communication by master to slaves at same time

Status
Not open for further replies.

vishnuk

Member level 1
Joined
Dec 8, 2017
Messages
38
Helped
1
Reputation
2
Reaction score
1
Trophy points
8
Location
Nandikkara
Activity points
297
Hi,

I need to know whether I can able to write data at the same time (by master) to two I2C devices (Slaves) of same address.
Please let me know if there is any chip (ICs) for acheiving this.
 

Hi,

Afaik this is not according I2C specification. I don´t recommend to do this.

"writing" only may work, but you can´t rely on ACK feedback.
"reading" may result in unreliable data. --> useless.

Klaus
 

Hi,

Only writing, No reading. Any chip available for help?
 

Hi,

Here the condition is single master and 2 slaves
 

Hi,

Any chip available for help?
I´m confused.
Master: --> any.
Slave: --> any that supports "write only". You need to specify it´s function.

Klaus
 

Hi,
I need to communicate or write to the registers of two image sensors simultaneously. master is a processor.
In between we will get any chip for controlling simultaneous communication?. Because every one says writing is possible but processor cant identify the ACK signals coming from which slave. So for managing that any chip available?
 
Last edited:

Hi,

again you give incomplete informations. Be more descriptive, or show a drawing.

What chip are you asking for?

*****
you said:
Only writing, No reading. Any chip available for help?
But now you talk about sensors. What sensors do you "write only"? --> very confusing.

Klaus
 

Hi,

We have two image sensors connected to same I2C bus with same address. We need to configure them by writing to their registers simultaneously. Is there any way to do so?. Whether "general call address" will help?
 

Hi,

I don´t understand what the problem is.

If both have the same address, then use this address, both ICs will be accessed. No need for a "general address call".

Klaus
 

If both have the same address, then use this address, both ICs will be accessed

But we need to know whether the writing was done successfully right?. Master cant identify whether any one of them failed, right? how to solve that?. thats my question.
 

This is pointless ))) you can't use two devices with same address on same bus. Nothing to discuss here.
 

Hi,

But we need to know whether the writing was done successfully right?. Master cant identify whether any one of them failed, right? how to solve that?. thats my question.
Isn´t it already answered in post#2.

If you want feedback from the sensors, --> then it is not "write only" anymore. You need to read.
Either read the ACK. --> answered post#2
or read back sensor contents. --> answered in post#2

****

Now it seems you don´t want to "write only" but: "write both simultaneously, and read them independently".
To do that you need a bus switch. (to generate a split bus, the two sensors on different branches)
Either a true I2C one like PCA9546
or simply "analog switches"

Klaus
 
  • Like
Reactions: vishnuk

    vishnuk

    Points: 2
    Helpful Answer Positive Rating
But we need to know whether the writing was done successfully right?. Master cant identify whether any one of them failed, right? how to solve that?. thats my question.

The way to solve the problem is to use an I2C multiplexer. Even at one off prices a 2 to 1 I2C mux only costs half a £$€.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top