Kakute H7 barometer I2C address?

Hardware Other Hardware
1

Hello,

I am using ArduPilot on a Kakute H7 flight controller. I am having an I2C address conflict with the on-board barometer (BMP280) at address 0x76; the conflicting address of my external I2C device cannot be changed.

I noticed that the BMP280 can be configured to use address 0x77 by pulling its SDO pin (#5) high. Does anyone know if this is supported/possible on the Kakute H7? Any insight or suggestions would be much appreciated!

Thanks,
Paul

2

HI paulblum,
I had the same problem!
The board BMP280 add 0x76 is firm on CL2 and CA2.
A second BMP280 can only be connected to CL1 and CL2 using 0x76.
As far as I know, and this is from Matek, 0x77 is not set as a valid I2C address;
May be this can be modified in the future?
Roy

3

That’s not a Kakute H7 though is it? Not really comparitive. Matek H743’s have 2xI2C, 2 IMU’s, an Sd card and the Kakute H7… doesn’t.

4

Hi Dave,
My bad!
I learned something today.
I did not realise all H7 were not created equally!
Sad, so much potential and not available when size matters.
.
I suppose the 0x77 address is not valid on all?
Is that a possible modification?

Roy

5

H7 is just the processor. The H743 is common across a lot of Flight Controllers but there is a lot more to these boards than that with significant differences across manufacturers.
I don’t have an answer to the I2C address question.

6

I reached out to Holybro with this question; the Kakute H7’s BMP280 SDO pin is connected directly to GND and its I2C address cannot be changed without hardware modification.

7

Hi Paulblum,
Sorry my reply was off target! I did not check the physical pin layout of the Holybro.

I’m still not sure if 0x77 would be accepted even if you did manage to change the SDO pin.
I did try and attach a second BMP280 to the same I2C input using 0x77 but it did not see it?