PCA9548A: Understanding functionality of PCA9548A

Hey Bojan,

I would recommend the TCA line up of this device over PCA. Our TCA line up is usually pin to pin, more cost competitive, solves some bugs seen from the PCA line up, and lastly some also support a wider voltage range.

"1) Can I connect multiple devices with different I2C addresses to the same output channel (SDn/SCn) of PCA9548A?"

-The general answer to this question is Yes, but you need to make sure they all support the pull up voltage that the bus is connected to.You also need to ensure that if you have two devices with the same address on different channels, you do not enable both channels.

(example: if channel 1 has a pull up voltage of 5V and you have multiple slaves but one only supports 3.3V max then this slave should be placed on a different channel with a max voltage of 3.3V.

"2) If affirmative, is it allowed that one of those I2C devicess connected to output channel has the same I2C address like PCA9548A switch ? E.G. to set 0x70 for I2C address of PCA9548A (with A0, A1, A2 inputs) and to have I2C device with address 0x70 connected to output channel SDn/SCn."

-No, this will cause issues when you send the 0x70 address and both the switch and the I2C device will ACK and potentially cause signal integrity problems if you perform a read.

It would be best if you change the HW address of the switch to a different address that does not conflict with other I2C devices.

Thanks,

-Bobby