[solved] Slave with Slaves (I2C)

Projects Networking, Protocols, and Devices
1

Hello everyone,

this may be a stranger question.

Is it possible to have an I2C Master-Slave arrangement, where the Slave also has I2C-Slaves itself?

Master (L1)
  - Slave1 (L1)
  - Slave2 (L1)
      -- Subslave21 (L2)
      -- Subslave22 (L2)
  - Slave3 (L1)
      -- Subslave31 (L2)
      -- Subslave32 (L2)

The toplevel (L1) uses a Raspberry as Master and Arduinos as Slaves (via I2C A4/5). Is it possible that the Arduinos also have slaves using I2C.
I do not want to share the I2C line with everything, since the Subslaves consists of the same chips and therefore have the same address. Also a I2C line through all components would exceed the length limit (if possible I would like not to use extenders).

Is it possible to allocate another 2 analog pins as additional I2C or is there a better way to go about it (maybe I2C to the slaves and SPI to the Subslaves).

Thanks for the help

2

Here is a sketch of what I am trying to say

Master_Slave_Slave.jpg
Master_Slave_Slave.jpg1450×1209 105 KB

Master_Slave_Slave.jpg
Master_Slave_Slave.jpg1450×1209 105 KB

3

A normal Nano only has one I2C port, but you could use a software I2C library to run the '2nd tier' slaves.

4

@Op

If you are talking about the following I2C topology, then (I think) it is possible. However, why do you think about it when the Master can handle as many as 127 I2C slaves?
sm64.png

sm64.png

5

The slaves (Level 1) all have to run some Chips (MCP3008, CAP1008, ...). Most of them have a version than can use SPI but not all.

Since it is not possible to set the address of most chips there would be a conflict if I use only one I2C-Bus.

@GolamMostafa: your sketch explains it very clearly. I will try SoftI2C (similar to SoftSpi some breakout board use) and open another topic if (when) problems arrive with the specific circuit.

Thanks everyone