I2C Communication Problem between NRF52840DK and a Bosch 688 Gas Sensor

[Alexander Feldman]

I have a BME688 connected to a NRF52840DK and I cannot get a working I2C communication using Zephyr. Below are all sources:

app.overlay

&pinctrl {
    i2c0_default: i2c0_default {
        group1 {
            psels = <NRF_PSEL(TWIM_SDA, 1, 10)>,
                    <NRF_PSEL(TWIM_SCL, 1, 11)>;
        };
    };
    i2c0_sleep: i2c0_sleep {
        group1 {
            psels = <NRF_PSEL(TWIM_SDA, 1, 10)>,
                    <NRF_PSEL(TWIM_SCL, 1, 11)>;
            low-power-enable;
        };
    };
};

&arduino_i2c {  
    bme688: bme688@76{
        status = "okay";
        reg = < 0x76 >;
    };
};

main.c

#include <stdlib.h>

#include <zephyr/types.h>
#include <zephyr/kernel.h>

#include <zephyr/drivers/i2c.h>

#define BME68X_REG_SOFT_RESET                     UINT8_C(0xe0)
#define BME68X_SOFT_RESET_CMD                     UINT8_C(0xb6)

static const struct i2c_dt_spec dev_i2c0 = I2C_DT_SPEC_GET(DT_NODELABEL(bme688));

int main()
{
    if (!device_is_ready(dev_i2c0.bus)) {
	printk("I2C bus %s is not ready.\n", dev_i2c0.bus->name);

	return EXIT_FAILURE;

    }

    int ret = i2c_reg_write_byte_dt(&dev_i2c0, BME68X_REG_SOFT_RESET, BME68X_SOFT_RESET_CMD);
    printk("i2c_reg_write_byte_dt: %d\n", ret);

    return EXIT_SUCCESS;
}

prj.conf

CONFIG_MAIN_STACK_SIZE=32768

CONFIG_GPIO=y

CONFIG_LOG=y
CONFIG_LOG_BUFFER_SIZE=32768
CONFIG_LOG_MODE_IMMEDIATE=y

CONFIG_I2C=y

I was wondering, what am I doing wrong.

[runsiv]

Hi Alexander

Do you get any build error or init error in your application? 

Could you try to add the following Kconfig 

CONFIG_BME68X_IAQ=y

Regards

Runar

[Alexander Feldman]

The problem turned out to be a hardware issue. Our custom BME breakout board was missing pull-up resistors. Trying the same firmware with an Adafruit BME breakout board solved the issue.