TIDUE59A May   2018  – September 2020

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5. 1System Description
    1. 1.1 Key System Specifications
  6. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 CC3220
      2. 2.3.2 CC2640R2F
      3. 2.3.3 DRV8837
    4. 2.4 System Design Theory
      1. 2.4.1 CC3220S to CC2640R2F Interface
      2. 2.4.2 CC3220S to DRV8837 Interface
      3. 2.4.3 Software Architecture
      4. 2.4.4 Network Connection Management
      5. 2.4.5 Provisioning
        1. 2.4.5.1 AP Provisioning and SmartConfig™
        2. 2.4.5.2 Wi-Fi Provisioning Over BLE
      6. 2.4.6 Sending and Receiving Messages Through Cloud
        1. 2.4.6.1 Message Queue Telemetry Transport Protocol
        2. 2.4.6.2 MQTT Client Implementation
      7. 2.4.7 Over-the-Air Updates
        1. 2.4.7.1 HyperText Transfer Protocol
      8. 2.4.8 Security Enablers
        1. 2.4.8.1 Secure Boot
        2. 2.4.8.2 Secure Sockets
          1. 2.4.8.2.1 Hardware Accelerators
          2. 2.4.8.2.2 Simple Network Time Protocol
        3. 2.4.8.3 File System Security
          1. 2.4.8.3.1 Failsafe Files and Bundle Protection
      9. 2.4.9 Low-Power Consumption
  7. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. 3.1.1.1 CC3220S LaunchPad™ Development Kit
        2. 3.1.1.2 CC2640R2F LaunchPad™ Development Kit
        3. 3.1.1.3 Sensor BoosterPack™ Connections (BMI160)
        4. 3.1.1.4 DRV8837EVM Modifications and Connections
        5. 3.1.1.5 Assembling EVMs
      2. 3.1.2 Software
        1. 3.1.2.1 Getting Started With Software
          1. 3.1.2.1.1 Build simple_np Application and Flash CC2640R2F
          2. 3.1.2.1.2 Use Premade UniFlash ImageCreator Project
          3. 3.1.2.1.3 Importing Project Source Files Into CCS
        2. 3.1.2.2 User Files
        3. 3.1.2.3 Run Wi-Fi® Doorlock Demo
          1. 3.1.2.3.1 Connect CC3220 to Network
          2. 3.1.2.3.2 Networking Functions
            1. 3.1.2.3.2.1 Get Current Date and Time (SNTP)
            2. 3.1.2.3.2.2 Send and Receive Messages (MQTT)
            3. 3.1.2.3.2.3 Perform Software Update Using Dropbox (OTA Update)
    2. 3.2 Testing and Results
      1. 3.2.1 Pass or Fail Tests
      2. 3.2.2 Power Measurements
      3. 3.2.3 Test Setup
        1. 3.2.3.1 CC3220S
        2. 3.2.3.2 CC2640R2F
        3. 3.2.3.3 DRV8837
      4. 3.2.4 Test Results
      5. 3.2.5 Battery Life Estimate
  8. 4Design Files
  9. 5Software Files
  10. 6Related Documentation
    1. 6.1 Trademarks
  11. 7Terminology
  12. 8About the Author
  13. 9Revision History

3.2.2 Power Measurements

Power consumption is a key design consideration for electronic smart locks, which are often battery-powered. Multiple power measurements were performed on the TIDC-01005 system and can be used to estimate the battery life of an electronic smart lock system using the featured devices. Specifically, the power consumed by the CC3220S (MCU host and Wi-Fi network processor), CC2640R2F (Bluetooth low energy wireless MCU), and the DRV8837 (low-voltage, brushed, DC motor driver) were measured, because the wireless connectivity and motor subsystems typically have the largest impact on the average system power consumption. The power measurements were performed without the sensors included by disabling the sensor thread in the software and removing the BOOSTXL-SENSORS from the test setup.

For the CC3220S, the power consumption was measured for various activities that occur during normal system operation. The power consumed while the CC3220S was being provisioned was not measured, because provisioning is only required for first-time system setup and is likely to occur only a few times over the product lifetime. During AP provisioning, the power consumption of the CC3220S is higher than during normal system operation, in which the CC3220S is configured as a station. The power consumed by the CC3220S during BLE provisioning reflects the MCU active power. Similar to provisioning, the power consumed during an OTA software update was not measured, because OTA updates typically occur only a few times over a product lifetime and are not expected to have a significant impact on the average power consumption of the system.

When the system has been provisioned and successfully connects to a Wi-Fi network, normal operation begins. During normal operation, the system attempts to keep the CC3220S MCU and the network processor in a low-power mode called LPDS, except for when the following occurs:

  • AP beacon reception or other broadcast occurs
  • Keep-alive message is sent to the AP
  • Keep-alive message is sent to the MQTT server
  • Message is received from the server
  • Message is sent to the server

The power consumption of the CC3220S was measured while the system was in an idle connected state (receiving AP beacons) and when the system received or sent messages to the MQTT broker. The power consumption of the CC2640R2F was measured during both BLE provisioning and while kept idle after provisioning. The power consumed by the DRV8837 was measured while the DRV8837 was driving a motor connected to a load and while held in sleep mode.