nRF Connect SDK library is sending the incorrect address to a sensor.

Question

I using a BMI323 sensor with address 0x68 on the I2C bus and a custom-made nRF52832 dev kit. when I tried to send some commands to the sensor via I2C, it didn't work.

here is the code (the code is kinda big so I just posted the important parts:

// variable that contains all I2C configurations
static const struct i2c_dt_spec bmi323 = I2C_DT_SPEC_GET(DT_NODELABEL(bmi323));

/*!
 * @brief This internal API reads I2C function map to COINES platform
 */
static BMI3_INTF_RET_TYPE bmi3_i2c_read(uint8_t reg_addr, uint8_t *reg_data, uint32_t len, void *intf_ptr)
{
    uint8_t device_addr = *(uint8_t*)intf_ptr;

    (void)intf_ptr;

    // burst read from the sensor
    i2c_burst_read_dt(&bmi323, reg_addr, reg_data, len);

    // although the best behaviour is to return one of the error codes defined in 'bmi3_defs.h" 
    // we will just return BMI3_INTF_RET_SUCCESS always for now
    return BMI3_INTF_RET_SUCCESS;
}

/*!
 * @brief This internal API writes I2C function map to COINES platform
 */
static BMI3_INTF_RET_TYPE bmi3_i2c_write(uint8_t reg_addr, const uint8_t *reg_data, uint32_t len, void *intf_ptr)
{
    uint8_t device_addr = *(uint8_t*)intf_ptr;

    (void)intf_ptr;

    // burst write from the sensor
    i2c_burst_write_dt(&bmi323, reg_addr, reg_data, len);

    // although the best behaviour is to return one of the error codes defined in 'bmi3_defs.h" 
    // we will just return BMI3_INTF_RET_SUCCESS always for now
    return BMI3_INTF_RET_SUCCESS;

}

here is the '.overlay' file:

// To get started, press Ctrl+Space to bring up the completion menu and view the available nodes.

// You can also use the buttons in the sidebar to perform actions on nodes.
// Actions currently available include:

// * Enabling / disabling the node
// * Adding the bus to a bus
// * Removing the node
// * Connecting ADC channels

// For more help, browse the DeviceTree documentation at https://docs.zephyrproject.org/latest/guides/dts/index.html
// You can also visit the nRF DeviceTree extension documentation at https://docs.nordicsemi.com/bundle/nrf-connect-vscode/page/guides/ncs_configure_app.html#devicetree-support-in-the-extension

&i2c0 {
	status = "okay";
	pinctrl-0 = <&i2c0_default>;
	pinctrl-names = "default";

    bmi323: bmi323@68{
        compatible = "i2c-device";
        reg = <0x68>;
        label="bmi323";
    };
};

&gpiote {
	status = "okay";
};

&pinctrl {
	i2c0_default: i2c0_default {
		group1 {
			psels = <NRF_PSEL(TWIM_SCL, 0, 8)>, <NRF_PSEL(TWIM_SDA, 0, 7)>;
		};
	};
};

I grabbed my logic analyzer and noticed the following on the I2C bus:

even though the address is specified to be 0x68 in the '.overlay' file, the actual address sent is '0xD0' where

0xD0 = 0x68 << 1;

I don't know. Is it a bug, or am I doing something wrong?

abdosalm · Accepted Answer

nvm, after further investigation. it's the logic analyzer that displays the address shifted lift by one. it has nothing to do with nRF connect SDK.

nRF Connect SDK library is sending the incorrect address to a sensor.

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