graph TD
    START[MPU reads @50ms = 20 Hz] --> A{IMU_CHANNEL<br/>try_send}
    
    A -->|Full| DROP1[❌ DROP: Channel full<br/>16 slots @ 50ms = 800ms buffer]
    A -->|OK| B[Main Loop receive]
    
    B --> C[Drain loop:<br/>Get freshest reading]
    C --> D{Time check:<br/>≥3s since last?}
    
    D -->|No| E[Skip MQTT]
    D -->|Yes| F{mqtt_set_imu<br/>try_lock IMU_LATEST}
    
    F -->|Locked| DROP2[❌ SKIP: Mutex busy]
    F -->|OK| G[Store payload]
    
    E --> H[show_imu]
    G --> H
    
    H --> I{DISPLAY_CHANNEL<br/>try_send}
    I -->|Full| DROP3[❌ DROP: Display slow<br/>8 slots @ 100ms = 800ms buffer]
    I -->|OK| J[Display renders]
    
    G --> K[MQTT Task loop]
    K --> L{IMU_LATEST<br/>try_lock}
    
    L -->|Empty/Locked| M[Skip this iteration]
    L -->|Has data| N[Send to broker<br/>QoS0 no retain]
    
    N --> O{TCP send result}
    O -->|Fail| RECONNECT[❌ Session dies<br/>Reconnect in 5s]
    O -->|OK| P[✅ Data sent]
    
    style DROP1 fill:#ffcccc
    style DROP2 fill:#ffcccc
    style DROP3 fill:#ffcccc
    style RECONNECT fill:#ffcccc
    style P fill:#ccffcc