init

I2C/components/scd30_driver/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+    SRCS "scd30.c"
+    INCLUDE_DIRS "."
+    REQUIRES driver
+)

I2C/components/scd30_driver/scd30.c

@@ -0,0 +1,82 @@
+#include "scd30.h"
+#include "driver/i2c_master.h"
+#include <string.h>
+#include <stdio.h>
+
+#define SCD30_I2C_ADDRESS 0x61
+#define SCD30_CMD_START_MEASUREMENT 0x0010
+#define SCD30_CMD_READ_DATA 0x0300
+#define SCD30_CMD_READY_STATUS 0x0202
+
+// Private function to calculate CRC-8
+static uint8_t calculate_crc8(const uint8_t *data, size_t len) {
+    const uint8_t polynomial = 0x31;
+    uint8_t crc = 0xFF;
+
+    for (size_t i = 0; i < len; i++) {
+        crc ^= data[i];
+        for (uint8_t bit = 0; bit < 8; bit++) {
+            if (crc & 0x80) {
+                crc = (crc << 1) ^ polynomial;
+            } else {
+                crc <<= 1;
+            }
+        }
+    }
+    return crc;
+}
+
+void scd30_init(void) {
+    i2c_master_config_t i2c_config = {
+        .scl_wait_us = 150000 // Clock stretching
+    };
+    i2c_master_init(I2C_NUM_0, &i2c_config);
+}
+
+void scd30_start_measurement(void) {
+    uint8_t command[5] = {
+        (SCD30_CMD_START_MEASUREMENT >> 8) & 0xFF,
+        SCD30_CMD_START_MEASUREMENT & 0xFF,
+        0x00, 0x10, // Argument for continuous measurement
+        0x00 // Placeholder for CRC
+    };
+    command[4] = calculate_crc8(&command[2], 2);
+
+    i2c_master_write_to_device(I2C_NUM_0, SCD30_I2C_ADDRESS, command, sizeof(command), 1000 / portTICK_PERIOD_MS);
+}
+
+int scd30_read_data(scd30_data_t *data) {
+    uint8_t ready_command[2] = {
+        (SCD30_CMD_READY_STATUS >> 8) & 0xFF,
+        SCD30_CMD_READY_STATUS & 0xFF
+    };
+    uint8_t ready_status[3];
+
+    // Poll until data is ready
+    do {
+        i2c_master_write_read_device(I2C_NUM_0, SCD30_I2C_ADDRESS, ready_command, sizeof(ready_command), ready_status, sizeof(ready_status), 1000 / portTICK_PERIOD_MS);
+    } while (ready_status[1] != 0x01);
+
+    uint8_t read_command[2] = {
+        (SCD30_CMD_READ_DATA >> 8) & 0xFF,
+        SCD30_CMD_READ_DATA & 0xFF
+    };
+    uint8_t buffer[18];
+
+    // Read 18 bytes of data
+    i2c_master_write_read_device(I2C_NUM_0, SCD30_I2C_ADDRESS, read_command, sizeof(read_command), buffer, sizeof(buffer), 1000 / portTICK_PERIOD_MS);
+
+    // Validate CRC for each pair of data
+    for (int i = 0; i < 18; i += 3) {
+        if (calculate_crc8(buffer + i, 2) != buffer[i + 2]) {
+            return -1; // CRC error
+        }
+    }
+
+    // Parse data
+    data->co2 = (float)((buffer[0] << 8) | buffer[1]);
+    data->temp = (float)((buffer[3] << 8) | buffer[4]);
+    data->humidity = (float)((buffer[6] << 8) | buffer[7]);
+
+    return 0; // Success
+}

I2C/components/scd30_driver/scd30.h

@@ -0,0 +1,18 @@
+#ifndef SCD30_H
+#define SCD30_H
+
+#include <stdint.h>
+
+// Data structure to hold SCD30 sensor data
+typedef struct {
+    float co2;      // CO2 concentration in ppm
+    float temp;     // Temperature in degrees Celsius
+    float humidity; // Relative humidity in percentage
+} scd30_data_t;
+
+// Function prototypes
+void scd30_init(void);
+void scd30_start_measurement(void);
+int scd30_read_data(scd30_data_t *data);
+
+#endif // SCD30_H