Using 4D display with another I2C device


I 'm just new on BB black and waiting to receive the dedicated cape display from 4D : 4D display
Looking at the documentation I saw that they use the 19 & 20 pins from header that are I2C2_SCL and I2C2_SDA.

My problem is that I want to use also the Sparkfun board MPU 9150 which is also I2C.

Is there any way to have both on Linux ?

Sorry, I2C is limited to 255 devices on it at a time. So, assuming that both those devices are different and have different addresses, you should have no issue communicating to both of them under Linux.


  • if the both are not masters
  • and if they don’t use the same address (as you said)

then I can plug the sparkfun MPU 9150 board on the 19-20 I2C2 pins behind the 4D display and have them working independently.

Is that right ?

Thank you Gerald for your answer .

If I understood well (and after read the docs) :

  • if the both are not masters
  • if they don’t use the same address

then I can plug the MPU 9150 on the header pins (19-20) for I2C2 and have the display also worlking.
is that right ?




Great! thanks

PS : sorry for the multiple messages

No problem. Gives me anotheropportunity to maybe get the word out to others. This is a common occurrence.


i2c address is only 7bit ,It should support up to 127 devices

another bit is for read/write

Well, that breaks it. So I guess it can’t support 2 devices then. My mistake.



Yes , you can connect with 2 devices in 1 i2c bus , if they have the different slave address .

I2C spec define 1r/w bit 7bit address , 9th bit ack from slave address .

You can detect it is i2cdetect -y 0 (0 means /dev/i2c-0 , maybe other bus address )

check your board-am335x-xxx.c

add in to i2c_board_info struct and ,you should write your own i2c driver for mpu 9150