• MCU: STM32WBA55UGI6 substitute for STM32WBA65PII7.
• Framework: STM32Cube HAL.
• Build system: STM32CubeIDE or STM32CubeMX generated CMake project.
• Wireless stack: ST STM32WBA BLE/802.15.4 middleware. Add application-specific advertising/commissioning after basic sensor bring-up.

• BME280: 0x76.
• BME688: 0x77.
• LIS2DW12: verify SA0 selection in final firmware; schematic straps SA0 low.
• TSL25911: fixed by device family, typically 0x29.
• SCD41: fixed by Sensirion driver.

1. Initialize clocks, GPIO, and watchdog.
2. Bring up UART console and PMS5003 UART.
3. Initialize I2C bus and scan addresses.
4. Initialize BME280, BME688, LIS2DW12, TSL25911, SCD41.
5. Initialize ADC channels for MiCS-6814 analog outputs.
6. Initialize SPI and reset/configure BGT60TR13C.
7. Initialize PDM microphone capture.
8. Initialize IR PWM at safe low duty cycle.
9. Start BLE/802.15.4 stack and publish telemetry.

• PB6/PB7: I2C, open-drain, pull-ups external.
• PA5/PA6/PA7: SPI master.
• PA2/PA3: USART at 9600 for PMS5003; optional debug output on same header only if firmware arbitrates usage.
• PA9/PA10: dedicated UART for USB-C debug console through CP2102N.
• PA8: GPIO output for status LED.
• PA0/PA1/PA11: ADC inputs, sample time high enough for external sensor source impedance.
• PA4: timer PWM output.
• PC13/PB8/PB9/PB1: EXTI inputs.
• PB0/PB2/PB3: GPIO outputs.
• PA13/PA14: SWD enabled.
• PH3_BOOT0: normal boot pulled low.

C
#include "main.h"
#include <string.h>
#include <stdio.h>

I2C_HandleTypeDef hi2c1;
SPI_HandleTypeDef hspi1;
UART_HandleTypeDef huart2;
UART_HandleTypeDef huart1;
ADC_HandleTypeDef hadc1;
TIM_HandleTypeDef htim2;

#define RADAR_CS_GPIO_Port      GPIOB
#define RADAR_CS_Pin            GPIO_PIN_0
#define RADAR_RESET_GPIO_Port   GPIOB
#define RADAR_RESET_Pin         GPIO_PIN_2
#define CAM_RESET_GPIO_Port     GPIOB
#define CAM_RESET_Pin           GPIO_PIN_3
#define IR_PWM_TIMER            htim2
#define IR_PWM_CHANNEL          TIM_CHANNEL_1
#define STATUS_LED_GPIO_Port    GPIOA
#define STATUS_LED_Pin          GPIO_PIN_8

#define BME280_ADDR             (0x76 << 1)
#define BME688_ADDR             (0x77 << 1)
#define TSL2591_ADDR            (0x29 << 1)

static void Error_Handler_User(const char *msg) {
    HAL_UART_Transmit(&huart2, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY);
    HAL_UART_Transmit(&huart2, (uint8_t*)"\r\n", 2, HAL_MAX_DELAY);
}

static uint8_t i2c_read_u8(uint16_t addr, uint8_t reg) {
    uint8_t value = 0;
    HAL_I2C_Mem_Read(&hi2c1, addr, reg, I2C_MEMADD_SIZE_8BIT, &value, 1, 100);
    return value;
}

static void i2c_write_u8(uint16_t addr, uint8_t reg, uint8_t value) {
    HAL_I2C_Mem_Write(&hi2c1, addr, reg, I2C_MEMADD_SIZE_8BIT, &value, 1, 100);
}

static void init_environment_sensors(void) {
    uint8_t id_bme280 = i2c_read_u8(BME280_ADDR, 0xD0);
    uint8_t id_bme688 = i2c_read_u8(BME688_ADDR, 0xD0);
    char msg[64];
    snprintf(msg, sizeof(msg), "BME280 ID=0x%02X BME688 ID=0x%02X", id_bme280, id_bme688);
    Error_Handler_User(msg);

    /* Basic forced-mode examples; replace with Bosch/Sensirion/ST production drivers. */
    i2c_write_u8(BME280_ADDR, 0xF4, 0x25);
    i2c_write_u8(BME688_ADDR, 0xF4, 0x25);
}

static void init_radar(void) {
    HAL_GPIO_WritePin(RADAR_CS_GPIO_Port, RADAR_CS_Pin, GPIO_PIN_SET);
    HAL_GPIO_WritePin(RADAR_RESET_GPIO_Port, RADAR_RESET_Pin, GPIO_PIN_RESET);
    HAL_Delay(10);
    HAL_GPIO_WritePin(RADAR_RESET_GPIO_Port, RADAR_RESET_Pin, GPIO_PIN_SET);
    HAL_Delay(50);
}

static void read_pms5003_frame(void) {
    uint8_t frame[32];
    if (HAL_UART_Receive(&huart2, frame, sizeof(frame), 1000) == HAL_OK) {
        if (frame[0] == 0x42 && frame[1] == 0x4D) {
            uint16_t pm25 = ((uint16_t)frame[12] << 8) | frame[13];
            char msg[64];
            snprintf(msg, sizeof(msg), "PM2.5=%u ug/m3", pm25);
            Error_Handler_User(msg);
        }
    }
}

static uint32_t read_adc_channel(uint32_t channel) {
    ADC_ChannelConfTypeDef sConfig = {0};
    sConfig.Channel = channel;
    sConfig.Rank = ADC_REGULAR_RANK_1;
    sConfig.SamplingTime = ADC_SAMPLETIME_247CYCLES_5;
    HAL_ADC_ConfigChannel(&hadc1, &sConfig);
    HAL_ADC_Start(&hadc1);
    HAL_ADC_PollForConversion(&hadc1, 100);
    uint32_t value = HAL_ADC_GetValue(&hadc1);
    HAL_ADC_Stop(&hadc1);
    return value;
}

static void set_ir_strobe_duty(uint16_t duty) {
    __HAL_TIM_SET_COMPARE(&IR_PWM_TIMER, IR_PWM_CHANNEL, duty);
}

int main(void) {
    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    MX_I2C1_Init();
    MX_SPI1_Init();
    MX_USART2_UART_Init();
    MX_USART1_UART_Init();
    MX_ADC1_Init();
    MX_TIM2_Init();

    HAL_TIM_PWM_Start(&IR_PWM_TIMER, IR_PWM_CHANNEL);
    set_ir_strobe_duty(0);

    Error_Handler_User("STM32WBA sensor node boot");
    HAL_GPIO_WritePin(STATUS_LED_GPIO_Port, STATUS_LED_Pin, GPIO_PIN_SET);
    init_environment_sensors();
    init_radar();

    while (1) {
        read_pms5003_frame();

        uint32_t nh3 = read_adc_channel(ADC_CHANNEL_0);   /* PA0 */
        uint32_t red = read_adc_channel(ADC_CHANNEL_1);   /* PA1 */
        uint32_t ox  = read_adc_channel(ADC_CHANNEL_15);  /* PA11 on many STM32 variants; verify CubeMX mapping */

        char msg[96];
        snprintf(msg, sizeof(msg), "ADC NH3=%lu RED=%lu OX=%lu", nh3, red, ox);
        Error_Handler_User(msg);

        HAL_Delay(5000);
        HAL_GPIO_TogglePin(STATUS_LED_GPIO_Port, STATUS_LED_Pin);
    }
}

1. Create an STM32CubeMX project for STM32WBA55UGI6.
2. Assign the pins from the mapping table.
3. Generate STM32 HAL project.
4. Add vendor drivers for Bosch BME280/BME688, ST LIS2DW12, Sensirion SCD4x, TSL2591, and Infineon BGT60TR13C.
5. Build in STM32CubeIDE or CMake.
6. Flash via SWD connector J2.

• Replace the register-level placeholder reads with vendor drivers.
• Route debug logs to the CP2102N USB-C console on PA9/PA10; keep PA2/PA3 dedicated to PMS5003 unless firmware explicitly arbitrates both uses.
• Add calibration routines for MiCS-6814; raw ADC values are not calibrated gas concentrations.
• Add sensor duty cycling to meet the 30-day energy budget.
• Add power-fault and brownout logging.
• Add BLE/802.15.4 telemetry format and security model.