SWRA657 June   2020 CC3100 , CC3200

 

  1.   SimpleLink Wi-Fi CC3100, CC3200 Serial Flash
    1.     Trademarks
    2. 1  Introduction
    3. 2  How File System Content Gets to the Serial Flash
    4. 3  File System Guidelines
    5. 4  User File Mathematics
    6. 5  System and Configuration Files
      1. 5.1 Description
      2. 5.2 Memory Consumption
        1. 5.2.1 CC3200 Use Case
        2. 5.2.2 Host Driver Mapping
        3. 5.2.3 Minimum Flash Size
    7. 6  Implementing File System Features From Host Processor
      1. 6.1 Overview
      2. 6.2 File Listing
        1. 6.2.1 Requirements
        2. 6.2.2 Procedure
      3. 6.3 Free/Occupied Space
        1. 6.3.1 Requirements
        2. 6.3.2 Procedure
      4. 6.4 File Appending
        1. 6.4.1 Requirements
        2. 6.4.2 Procedure
    8. 7  Factors to Consider in Designing With Serial Flash
      1. 7.1 Serial Flash Vendor and Part Number Selection
      2. 7.2 Supported Flash Types
      3. 7.3 Frequent Write Operations
        1. 7.3.1 Serial Flash Access by the Wi-Fi System"
        2. 7.3.2 Seral Flash Access by the WiFi System
          1. 7.3.2.1 System Files
          2. 7.3.2.2 User Files
      4. 7.4 Sudden Power Off (power removal during a write/erase phase)
        1. 7.4.1 Battery Powered Systems
        2. 7.4.2 Line Powered Systems
    9. 8  Design Recommendations for Ensuring the Integrity of the Power Supply to the Serial Flash
      1. 8.1 Overview
      2. 8.2 Key Points
      3. 8.3 Brown-Out Mitigation Techniques for New Self-Hosted CC3200 Designs
    10. 9  Recommended Best Practices
    11. 10 Implications of Data Integrity Compromise to CC3100/CC3200
      1. 10.1 Recovery
    12. 11 References

7.4.2 Line Powered Systems

In an AC line powered system, the failure of the grid can cause the supply of the Wi-Fi subsystem to drop suddenly. In the unlikely event this coincides with the erase operation of the serial flash, there is a chance of data corruption. One of the ways to minimize the chance of a flash corruption would be to ensure that the DC voltage ramps down slowly after the input power is removed. This can be achieved with the help of bulk capacitors which hold the charge while input supply is removed. The embedded system would sense the sudden fall in the input voltage and then initiate a soft shutdown of the Wi-Fi sub-system thereby safely completing all serial flash operations before Vflash-min is reached. The charge stored on the capacitor would be used during this brief interval. Such a sequence is illustrated in Figure 6.

swra657-serial-flash-corruption-avoided-through-use-of-a-bulk-capacitor.pngFigure 6. Serial Flash Corruption Avoided Through Use of a Bulk Capacitor