TCA9548A-Q1: can set I2C target address same as the device I2C address?

Zhou Yana

Prodigy 10 points

Part Number: TCA9548A-Q1

Tool/software:

can set I2C target address same as the device I2C address?

example: TCA9548 0X74,target address also set as 0X74?

1 month ago

0 Clemens Ladisch 1 month ago

Guru 277020 points

No; all devices on all enabled channels must have unique addresses.

0 Zhou Yana 1 month ago in reply to Clemens Ladisch

Prodigy 10 points

So, not only the device address needs to be different from the other 8 target addresses,but the 8 target addresses also need to be different?

0 Clemens Ladisch 1 month ago in reply to Zhou Yana

Guru 277020 points

It appears there is a misunderstanding. Please show your system architecture with all I²C addresses.

When you want to access the TCA9548A-Q1's control register, then you have to use address 0x74 (or whatever is configured with A0/A1/A2).
When you want to access another device, then you have to use the address of that device (which must be different from 0x74).

0 Zhou Yana 1 month ago in reply to Clemens Ladisch

Prodigy 10 points

example：devices 1.1-1.8 can use 0X70 address?,devices 2.1-2.8 can use 0x70 address?

0 Zhou Yana 1 month ago in reply to Zhou Yana

Prodigy 10 points

sorry，add a question:can device 1.1-1.8 use same address?

+1 Kameron Hill 1 month ago in reply to Zhou Yana

TI__Genius 15200 points

Hello Zhou,

Like Clemens said the address of different devices on the i2c bus must be different for proper communication.

If not you will run into something called address conflict.

Check out this App note which talks about several ways the problem can be solved.

Please let me know what you think after reading this and we can look into a solution for this further.

Regards,

kameron

0 Clemens Ladisch 1 month ago in reply to Kameron Hill

Guru 277020 points

The addresses 0x70 and 0x74 are already used by the two switches. When the master sends a command to address 0x70 and 0x74, then one of the switches will act on it. So it is not allowed for another device on any of the buses 1.1…1.8 or 2.1…2.8 to have address 0x70 or 0x74. All other addresses are allowed.

Multiple devices on those channels can have the same address, as long as only one of those channels is enabled at the same time.

0 Zhou Yana 1 month ago in reply to Clemens Ladisch

Prodigy 10 points

thank u,got it.

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TCA9548A-Q1: can set I2C target address same as the device I2C address?