SLAU533D September   2013  – April 2017

 

  1.   MSP430F5529 LaunchPad™ Development Kit (MSP‑EXP430F5529LP)
    1.     Trademarks
    2. 1 Getting Started
      1. 1.1 Key Features
      2. 1.2 Kit Contents
      3. 1.3 Out-of-Box Experience
        1. 1.3.1 Step 1: Install a Software Development Platform
        2. 1.3.2 Step 2: Connect the Hardware
        3. 1.3.3 Step 3: Verify the storage volume has been loaded
        4. 1.3.4 Step 4: Open a text editor, and press the buttons
        5. 1.3.5 Step 5: Customize the strings
    3. 2 Hardware
      1. 2.1 Block Diagram
      2. 2.2 Hardware Features
        1. 2.2.1 MSP430F5529
        2. 2.2.2 eZ-FET lite Onboard Emulator
        3. 2.2.3 Integrated Full-Speed USB Hub
        4. 2.2.4 Power
        5. 2.2.5 Clocking
        6. 2.2.6 Application (or "Backchannel") UART
        7. 2.2.7 Emulator and Target Isolation Jumper Block
        8. 2.2.8 Isolation Jumper Block: 3.3-V and 5-V Jumpers
        9. 2.2.9 Isolation Jumper Block: Emulator Connection and Application UART
      3. 2.3 Measure Current Draw of MSP430 MCU
      4. 2.4 Using an External Power Source
        1. 2.4.1 External 3.3-V Power Source
        2. 2.4.2 External 5-V Power Source Without USB Connection
        3. 2.4.3 External 5-V Power Source With USB Connection
      5. 2.5 Using the eZ-FET lite Emulator With a Different Target
      6. 2.6 USB BSL Button
      7. 2.7 BoosterPack Plug-in Module Pinout
      8. 2.8 Design Files
      9. 2.9 Hardware Change Log
    4. 3 Software Examples
      1. 3.1 MSP430 Software Libraries: driverlib and the USB API
      2. 3.2 Viewing the Code
        1. 3.2.1 CCS
        2. 3.2.2 IAR
      3. 3.3 Example Project Software Organization
      4. 3.4 USB Configuration Files
      5. 3.5 Out-of-Box Experience: emulStorageKeyboard
        1. 3.5.1  Flowchart
        2. 3.5.2  Pre-Initialization
        3. 3.5.3  Initialization
          1. 3.5.3.1 Configuring the Keyboard
          2. 3.5.3.2 Configuring the MSC Interface
        4. 3.5.4  Handling SCSI Commands
        5. 3.5.5  LPM0 Entry
        6. 3.5.6  LPM0 Exit
        7. 3.5.7  Emulated Storage Volume
        8. 3.5.8  Sending Data as a USB Keyboard
        9. 3.5.9  Properly Handling USB Unplug Events
        10. 3.5.10 Non-Maskable Interrupt (NMI) Vector
      6. 3.6 Example: simpleUsbBackchannel
        1. 3.6.1 What It Does
        2. 3.6.2 Installing the CDC Interface
        3. 3.6.3 Operating the Example
        4. 3.6.4 Backchannel UART Library: bcUart.c, bcUart.h
        5. 3.6.5 Code Description: Initialization
          1. 3.6.5.1 Stopping the Watchdog
          2. 3.6.5.2 Configuring VCORE
          3. 3.6.5.3 Configuring Clocks
          4. 3.6.5.4 Configuring Ports
          5. 3.6.5.5 Initializing the Backchannel UART
          6. 3.6.5.6 Configuring USB
        6. 3.6.6 Code Description: Main Loop
        7. 3.6.7 Modifying to Use an HID-Datapipe Interface
      7. 3.7 Starting Device Manager
    5. 4 Additional Resources
      1. 4.1 LaunchPad Development Kit Websites
      2. 4.2 Information on the MSP430F5529
      3. 4.3 Download CCS, IAR, mspgcc, or Energia
      4. 4.4 USB Developers Package
      5. 4.5 MSP430Ware and TI Resource Explorer
      6. 4.6 F5529 Code Examples
      7. 4.7 MSP430 Application Notes
      8. 4.8 TI E2E Community
      9. 4.9 Community at Large
    6. 5 FAQs
    7. 6 Schematics
  2.   Revision History

3.5.10 Non-Maskable Interrupt (NMI) Vector

The MSP430 contains one vector that cannot be disabled by the general interrupt enable (GIE) bit: the NMI vector. Several different events are directed into the NMI vector, most of which involve critical functions. Oscillator failure is one example.

There is one NMI unique to USB operation: the "bus error", which is indicated when the SYSUNIV interrupt vector register contains the value SYSUNIV_BUSIFG. This involves the fact that the MSP430 USB module shares a block of RAM with the CPU, called "USB RAM". When the host suspends the USB module, it becomes clocked by a slow clock. If the CPU then tries to access USB RAM, the difference in clock speeds between this slow clock and the MCU clock creates a conflict, and recovery from the error is not possible without shutting down the USB module.

Fortunately this event is completely within control of software, by not accessing USB RAM during suspend. The USB API is written to not do this, and most applications do not have a reason to access USB RAM. Therefore, this error should never occur. But in the event that it does, the NMI is provided, and code is provided to handle the failure.