Not found I2C slave address for 96Boards Sensors Mezzanine adapter from RTOS on Ultra96 board

Products Support Ultra96
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#1

Hello.

I can’t find the I2C sensor for the 96Boards Sensors Mezzanine adapter from the RTOS on the Ultra96 board. Am I doing it wrong?

I have an Ultra96 v1 ​​board and a 96boards Sensors Mezzanine adapter. I want to get the value from the sensor on the Sensors Mezzanine adapter via I2C_1 port from Cortex-R5 (xilinx-freertos) on the Ultra96 board. I used the overlay file for Sensors96 for the hardware of the Ultra96 board. (https://github.com/Avnet/Ultra96-PYNQ/tree/master/Ultra96/sensors96b)
In Addition, RTOS uses the iicps driver for I2C communication.

When I use the iicps driver to search for slave addresses on an Ultra96 board, I can always find two values. (0x75,0xF5) However, this address can be detected without the mezzanine board. Also, no signal is output from the I2C_1 port even if communication is started.

#2

Do you have any sensors or other i2c devices actually plugged into it?

#3

Yes. I think the board is connected.
I make sure that the power LEDs on the mezzanine and sensor boards are lit.

Below is the photo.

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_20201113_0912322159×1741 782 KB

#4

I have concerns over the sensor you are attaching.

  1. you are feeding it 5v, likely because it has a built in voltage regulator, but can that sensor accept 5v I/o?

  2. all those passive components with that sensor suggests that the little board may have i2c pull up resistors built in. What voltage are they pulling up to? Likely less than 5v. The sensor mezzanine has its own pull up resistors and expects peripherals that do NOT have additional pull ups.

You may have better luck plugging into one of the 3.3v plugs on the mezzanine, but you really need to get a better understanding of what that other board is you’re plugging into it. You may need to remove some pull up resistors from it. Probably a good idea to probe the i2c lines to see what is actually going on.

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