Other Parts Discussed in Thread: TCA9536, TMP102, PCA9536, INA238, INA228, INA226, INA237
I am using 5 x INA236 devices in the design. They are living on a single sided MCPCB, so signal routing is very limited. The issue is that I have only a single I2C Bus on the PCB available, so switching via A0 Pin (like a chip select) is considered. However in order to generate the A0 switching we want to use a I2C GPIO Expander (e.g. TCA9536/7) to dynamically switch the I2C addresses:
1 device gets address 0x43 (A0 tied to SCL)
1 device gets address 0x42 (A0 tied to SDA)
the remaining 3 devices getting dynamically switched A0 between VDD/GND resulting in Adressen 0x40 / 0x41
The issue now is that the GPIO Expander uses address 0x41, ouch x-) which is in conflict.
Using the INA236B with a different address is also not possible, since each INA236 device is accompanied with a TMP102.
This device sits on Address 0x48, 0x49, 0x4A, 0x4B... same as INA236B!
Currently there is only 1 select line going to each INA236, TMP102 block (where INA236 A0 and TMP102 ADD0 are tied together).
So I ran out of options and need to redesign. One idea would be use the common select signal to switch between GND and either SDA or SCL avoiding the address conflict with the PCA9536 (0x41) device. Here comes the question: how to do this in a simple way, so it fits on the current single sided design? I am considering to use a simple FET or transistor to pull e.g. SCL to the A0 / ADD0 inputs. Any idea if this could work, or other considerations are welcome, too.
Thank you for at least reading
Kai
