Facing issue in connecting SHT40 with Circuitdojo_feather_nrf9151

Question

Hi,
I have purchase a circuitdojo_feather_nrf9151 board it has LIS2DH12 and npm1300 on i2c2 i also want to connect SHT40 but facing issue this sensor is not detecting on i2c pins. I have tested this sensor with other controller like esp32 it is working

i am getting following logs

[00:00:05.199,737] <inf> sensors: Scanning I2C2 bus...
[00:00:05.203,948] <inf> sensors: Found: 0x19
[00:00:05.222,747] <inf> sensors: Found: 0x6B
[00:00:05.225,524] <inf> sensors: Sensors: modem ready
[00:00:05.231,231] <err> SHT4X: Invalid CRC for RH.
[00:00:05.231,231] <err> SHT4X: Failed to fetch data.
[00:00:05.231,262] <wrn> sensors: SHT40 fetch failed: -5
[00:00:05.231,262] <wrn> sensors: SHT40 unavailable, falling back to modem temperature

#if DT_HAS_ALIAS(sht40)
static const struct device *sht40_dev = DEVICE_DT_GET(DT_ALIAS(sht40));
#else
static const struct device *sht40_dev = NULL;
#endif   
   
    
    static bool read_sht40(int16_t *temp_c_x10, uint8_t *humidity_pct)
{
    if (!sht40_dev || !device_is_ready(sht40_dev)) {
        LOG_WRN("SHT40 not ready");
        return false;
    }

    int err = sensor_sample_fetch(sht40_dev);
    if (err) {
        LOG_WRN("SHT40 fetch failed: %d", err);
        return false;
    }

    struct sensor_value temp, hum;

    err = sensor_channel_get(sht40_dev, SENSOR_CHAN_AMBIENT_TEMP, &temp);
    if (err) {
        LOG_WRN("SHT40 temp get failed: %d", err);
        return false;
    }

    err = sensor_channel_get(sht40_dev, SENSOR_CHAN_HUMIDITY, &hum);
    if (err) {
        LOG_WRN("SHT40 humidity get failed: %d", err);
        return false;
    }

    /*
     * sensor_value { int32_t val1; int32_t val2; }
     * val1 = integer part, val2 = fractional part (millionths).
     * We store temperature × 10 for 0.1 °C resolution.
     *
     * Example: 23.56 °C → val1=23, val2=560000 → temp_c_x10 = 235
     */
    *temp_c_x10 = (int16_t)(temp.val1 * 10 + temp.val2 / 100000);

    /*
     * Humidity: clamp to 0–100 %, rounding to nearest integer.
     */
    int32_t hum_int = hum.val1;
    if (hum_int < 0)   hum_int = 0;
    if (hum_int > 100) hum_int = 100;
    *humidity_pct = (uint8_t)hum_int;

    LOG_INF("SHT40: temp=%d.%d °C  hum=%u %%",
            *temp_c_x10 / 10, abs(*temp_c_x10 % 10), *humidity_pct);

    return true;
}
    
    
    
    if (sht40_dev && device_is_ready(sht40_dev)) {
        LOG_INF("SHT40 ready on I2C — using as primary temperature source");
    } else {
        LOG_WRN("SHT40 not found — falling back to modem AT%%XTEMP?");
    }    

    /* Temporary — remove after confirming SHT40 is found */
    const struct device *i2c2_bus = DEVICE_DT_GET(DT_NODELABEL(i2c2));
    if (device_is_ready(i2c2_bus)) {
        LOG_INF("Scanning I2C2 bus...");
        for (uint8_t addr = 0x08; addr < 0x78; addr++) {
            uint8_t dummy;
            if (i2c_read(i2c2_bus, &dummy, 1, addr) == 0) {
                LOG_INF("  Found: 0x%02X", addr);
            }
        }
    } else {
        LOG_ERR("I2C2 bus not ready!");
    }
    
    
    
    my overlay
    
    
    / {
    aliases {
        uart-bridge = &uart1;
        sht40 = &sht40;
    };
};

&uart1 {
    status = "okay";
    current-speed = <115200>;
};

&i2c2 {
    clock-frequency = <I2C_BITRATE_STANDARD>;
	npm1300_pmic: pmic@6b {
		compatible = "nordic,npm1300";
		reg = <0x6b>;

		npm1300_leds: leds {
			compatible = "nordic,npm1300-led";
			nordic,led0-mode = "host";
			nordic,led1-mode = "host";
			nordic,led2-mode = "host";
		};

	};
    sht40: sht40@44 {
        compatible = "sensirion,sht4x";
        reg = <0x44>;
        repeatability = <1>;
    };
};


in prj.conf
CONFIG_I2C=y
CONFIG_SENSOR=y
CONFIG_LIS2DH=y
CONFIG_SHT4X=y

NamanShandilya · Answer

Hi,
3223.Session 0.sal

The attached file is the logic analyser session file in this i am not geting any traffic from SHT40 sensor but i am able to get data from LIS2dh and npm1300 you can see.

This is my prj.conf file

#

# prj.conf — nRF9151 Feather IoT Lock Application

#

# ── General ───────────────────────────────────────────────────────────────────

CONFIG_ASSERT=y

CONFIG_REBOOT=y

CONFIG_GRIT_FW_VERSION="1.0.0"

# ── Logging ───────────────────────────────────────────────────────────────────

CONFIG_LOG=y

CONFIG_LOG_MODE_DEFERRED=y

CONFIG_STDOUT_CONSOLE=y

CONFIG_UART_INTERRUPT_DRIVEN=y

CONFIG_LOG_BUFFER_SIZE=4096

# ── Modem ─────────────────────────────────────────────────────────────────────

CONFIG_NRF_MODEM_LIB=y

CONFIG_MODEM_INFO=y

CONFIG_MODEM_INFO_ADD_NETWORK=y

# ── LTE Link Controller ───────────────────────────────────────────────────────

CONFIG_LTE_LINK_CONTROL=y

CONFIG_LTE_MODE_PREFERENCE_LTE_M=y

CONFIG_LTE_LC_PSM_MODULE=y

CONFIG_LTE_PSM_REQ=y

CONFIG_LTE_LC_EDRX_MODULE=y

# ── GNSS ──────────────────────────────────────────────────────────────────────

CONFIG_GNSS=y

CONFIG_FPU=y

# ── Antenna / Coexistence ─────────────────────────────────────────────────────

CONFIG_MODEM_ANTENNA=y

CONFIG_MODEM_ANTENNA_AT_MAGPIO=""

CONFIG_MODEM_ANTENNA_AT_COEX0="AT%XCOEX0=1,1,1574,1577"

# ── Networking ────────────────────────────────────────────────────────────────

CONFIG_NETWORKING=y

CONFIG_NET_NATIVE=n

CONFIG_NET_SOCKETS=y

CONFIG_NET_SOCKETS_OFFLOAD=y

CONFIG_NET_IPV4=y

CONFIG_NET_IPV6=y

CONFIG_NET_TCP=y

CONFIG_PDN=y

# ── MQTT (TLS on port 8883) ───────────────────────────────────────────────────

CONFIG_MQTT_HELPER=y

CONFIG_MQTT_CLEAN_SESSION=y

CONFIG_MQTT_KEEPALIVE=60

CONFIG_MQTT_HELPER_RX_TX_BUFFER_SIZE=2048

CONFIG_MQTT_HELPER_PAYLOAD_BUFFER_LEN=1024

CONFIG_MQTT_HELPER_SEC_TAG=1

CONFIG_MQTT_LIB=y

CONFIG_MQTT_LIB_TLS=y

CONFIG_MODEM_KEY_MGMT=y

# ── FOTA / Firmware Over The Air ──────────────────────────────────────────────

# NCS v2.7: FOTA_DOWNLOAD depends on DOWNLOADER (not DOWNLOAD_CLIENT).

# DOWNLOAD_CLIENT is the older deprecated API; DOWNLOADER is the replacement.

CONFIG_DOWNLOADER=y

CONFIG_DOWNLOADER_STACK_SIZE=4096

CONFIG_FOTA_DOWNLOAD=y

CONFIG_FOTA_DOWNLOAD_PROGRESS_EVT=y

CONFIG_DFU_TARGET=y

CONFIG_DFU_TARGET_MCUBOOT=y

CONFIG_IMG_MANAGER=y

CONFIG_BOOTLOADER_MCUBOOT=y

# TLS for HTTPS firmware download uses the same CA cert tag as MQTT (tag 1).

# To use a separate tag, set CONFIG_DOWNLOADER_TLS_SESSION_CACHE_ENTRIES and

# pass the tag number directly to fota_download_start() in transport.c.

# ── Hardware ID (IMEI as MQTT client ID) ──────────────────────────────────────

CONFIG_HW_ID_LIBRARY=y

CONFIG_HW_ID_LIBRARY_SOURCE_IMEI=y

# ── ZBus ─────────────────────────────────────────────────────────────────────

CONFIG_ZBUS=y

# ── State Machine Framework ───────────────────────────────────────────────────

CONFIG_SMF=y

# ── Math library ──────────────────────────────────────────────────────────────

CONFIG_NEWLIB_LIBC=y

CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y

# ── GPIO ──────────────────────────────────────────────────────────────────────

CONFIG_GPIO=y

CONFIG_GPIO_NRFX=y

# ── I2C ───────────────────────────────────────────────────────────────────────

CONFIG_I2C=y

CONFIG_SENSOR=y

# ── Accelerometer — LIS2DH12 on I2C2 (SCL=P0.01 SDA=P0.02) ──────────────────

# INT1=P0.20 (shock/tamper)

CONFIG_LIS2DH=y

# Disable driver-managed trigger — we handle INT1 via raw GPIO ISR

# (accel_int1_handler in sensors.c) and submit a k_work item.

# Enabling TRIGGER_GLOBAL_THREAD here AND gpio_add_callback() on the

# same pin causes double-firing of tamper events.

CONFIG_LIS2DH_TRIGGER_NONE=y

# ── npm1300 PMIC / Charger / Fuel gauge ───────────────────────────────────────

# npm1300 charger exposes SENSOR_CHAN_GAUGE_VOLTAGE + GAUGE_STATE_OF_CHARGE.

# Correct channel is SENSOR_CHAN_GAUGE_VOLTAGE (not SENSOR_CHAN_VOLTAGE).

# CONFIG_REGULATOR=y is needed so the MFD subsystem fully initialises npm1300.

CONFIG_MFD_NPM1300=y

CONFIG_REGULATOR=y

CONFIG_REGULATOR_NPM1300=y

CONFIG_NPM1300_CHARGER=y

# ── NVS — Non-Volatile Storage for event log persistence ─────────────────────

CONFIG_NVS=y

CONFIG_FLASH=y

CONFIG_FLASH_PAGE_LAYOUT=y

CONFIG_FLASH_MAP=y

CONFIG_STREAM_FLASH=y

# ── UART (nRF54L15 BLE bridge) ────────────────────────────────────────────────

# uart3 pins (P0.26 TX / P0.27 RX) and sleep state already defined in board DTS.

CONFIG_UART_BRIDGE_DEV="UART_3"

# ── Memory ────────────────────────────────────────────────────────────────────

CONFIG_HEAP_MEM_POOL_SIZE=57344

CONFIG_MAIN_STACK_SIZE=4096

CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096

CONFIG_SYSTEM_WORKQUEUE_PRIORITY=5

# ── AT monitor ────────────────────────────────────────────────────────────────

CONFIG_AT_MONITOR=y

CONFIG_AT_MONITOR_HEAP_SIZE=1024

# ── APN ───────────────────────────────────────────────────────────────────────

CONFIG_PDN_DEFAULTS_OVERRIDE=y

CONFIG_PDN_DEFAULT_APN="airtelgprs.com"

# ── Application config ────────────────────────────────────────────────────────

CONFIG_TRIGGER_INTERVAL_S=30

CONFIG_MQTT_BROKER_HOSTNAME="your-mqtt-broker.example.com"

CONFIG_MQTT_BROKER_PORT=8883

# ── Boot banner ───────────────────────────────────────────────────────────────

CONFIG_BOOT_BANNER=n

CONFIG_NCS_BOOT_BANNER=n

# ── Memory diagnostics ────────────────────────────────────────────────────────

CONFIG_THREAD_STACK_INFO=y

CONFIG_THREAD_MONITOR=y

CONFIG_THREAD_NAME=y

CONFIG_SYS_HEAP_RUNTIME_STATS=y

CONFIG_THREAD_ANALYZER=y

# ── SHT40 Temperature & Humidity Sensor ──────────────────────────────────────

CONFIG_SHT4X=y

# Disable TF-M logging completely

CONFIG_TFM_LOG_LEVEL_SILENCE=y

this the device tree generated in build folder

i2c2: i2c@a000 {

compatible = "nordic,nrf-twim";

#address-cells = < 0x1 >;

#size-cells = < 0x0 >;

reg = < 0xa000 0x1000 >;

interrupts = < 0xa 0x1 >;

easydma-maxcnt-bits = < 0xd >;

status = "okay";

zephyr,pm-device-runtime-auto;

pinctrl-0 = < &i2c2_default >;

pinctrl-1 = < &i2c2_sleep >;

pinctrl-names = "default", "sleep";

clock-frequency = < 0x61a80 >;

lis2dh: lis2dh@19 {

compatible = "st,lis2dh";

reg = < 0x19 >;

irq-gpios = < &gpio0 0x13 0x0 >, < &gpio0 0xc 0x0 >;

};

npm1300_pmic: pmic@6b {

compatible = "nordic,npm1300";

host-int-gpios = < &gpio0 0x8 0x0 >;

pmic-int-pin = < 0x1 >;

reg = < 0x6b >;

npm1300_gpio: gpio-controller {

compatible = "nordic,npm1300-gpio";

gpio-controller;

#gpio-cells = < 0x2 >;

ngpios = < 0x5 >;

};

npm1300_leds: leds {

compatible = "nordic,npm1300-led";

nordic,led0-mode = "host";

nordic,led1-mode = "host";

nordic,led2-mode = "host";

};

npm1300_charger: charger {

compatible = "nordic,npm1300-charger";

term-microvolt = < 0x3f52f0 >;

term-warm-microvolt = < 0x3d0900 >;

current-microamp = < 0xafc80 >;

dischg-limit-microamp = < 0xf4240 >;

vbus-limit-microamp = < 0xf4240 >;

thermistor-ohms = < 0x2710 >;

thermistor-beta = < 0xd34 >;

charging-enable;

};

npm1300_regulators: regulators {

compatible = "nordic,npm1300-regulator";

npm1300_buck1: BUCK1 {

regulator-min-microvolt = < 0x325aa0 >;

regulator-max-microvolt = < 0x325aa0 >;

regulator-always-on;

};

npm1300_buck2: BUCK2 {

regulator-min-microvolt = < 0x325aa0 >;

regulator-max-microvolt = < 0x325aa0 >;

};

sht40: sht40@44 {

compatible = "sensirion,sht4x";

reg = < 0x44 >;

repeatability = < 0x2 >;

};

I have also tested using BMA456 attached to the same I2C pins, but this also did not work. The voltage on the scl and sda pins is 3.3V. I have tested using a multimeter.