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
