SDAA486 September   2026 CC1312R

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Smart Meter EU Regulations
    2. 1.2 Rotary Metrology Designs
  5. 2Smart Flow Meters and Sub-Metering Devices
    1. 2.1 Heat Cost Allocator (Sub-Metering)
      1. 2.1.1 HCA Key Functions
        1. 2.1.1.1 IrDA Communication Port
        2. 2.1.1.2 Temperature Measurement (Two-Sensor Method)
        3. 2.1.1.3 Segment LCD Support
    2. 2.2 Retrofit Add-On Module for Mechanical Water Meters
      1. 2.2.1 Retrofit Add-On Module Key Functions
      2. 2.2.2 Rotary Flow Metrology Implementation
        1. 2.2.2.1 Optical and Magnetic Rotary Sensing
        2. 2.2.2.2 Inductive Rotary Sensing
      3. 2.2.3 IrDA Wake-Up Detection
    3. 2.3 Smart Rotary Water Meter
      1. 2.3.1 Water Meter Key Functions
      2. 2.3.2 Segment LCD with CapTouch Activation
      3. 2.3.3 Tamper Detection With TMAG5231
      4. 2.3.4 OMS Compliant wM-Bus Communication Sub-system
    4. 2.4 Thermal Meters (Heat / Cold)
      1. 2.4.1 Thermal Meter Key Functions
      2. 2.4.2 Analog Signal Chain for DTM
      3. 2.4.3 Remarkable, Fully Digital Design for DTM
        1. 2.4.3.1 I2C and SMBus-Compatible Digital Sensor for Thermal Meters
        2. 2.4.3.2 1-Wire Compatible Digital Sensor for Thermal Meters
    5. 2.5 Bluetooth Low Energy (BLE) in Flow Meters
    6. 2.6 Influence of CRA on Smart Flow Meters and Heat Cost Allocators
      1. 2.6.1 Achieving CRA Conformance Through Careful System Design
        1. 2.6.1.1 Tamper Detection as a Physical Security Argument
        2. 2.6.1.2 Secure Key Storage
        3. 2.6.1.3 Secure Boot
        4. 2.6.1.4 Authenticated wM-Bus Communication
        5. 2.6.1.5 Secure Firmware Update via Over-the-Air Download (OAD)
        6. 2.6.1.6 Security Event Logging
  6. 3Summary
  7. 4References

2.2.1 Retrofit Add-On Module Key Functions

The block diagram, as shown in Figure 2-3, integrates these sub-systems, all controlled by the CRA capable CC1312R Wireless MCU running applications code and the Sub-1GHz wireless protocol (for example, OMS wM-Bus v4.2.1 or v5.0.1):

  1. IrDA half- or full-duplex port
  2. Sub-1GHz Radio (uni-directional or bi-directional) with external Balun/RF Filter and Antenna (same as for HCA)
  3. Tamper detection (Retrofit AddOn module removal from the mechanical Water Meter or detection of strong magnetic fields near the unit – same/very similar to HCA)
  4. Metrology for rotary movement: either optical or inductive or magnetic (flow metrology sub-system)
Note: Capacitive sensing designs for rotary detection also exist, though these are much less widespread, so they are not reviewed in this document.