SWRU271I October   2010  – January 2020 CC2540 , CC2540T , CC2541 , CC2541-Q1 , CC2640R2F

 

  1.   Preface
    1.     Trademarks
    2.     Related Documentation
  2. 1Overview
    1. 1.1 Support Note
    2. 1.2 Introduction
    3. 1.3 Bluetooth Low Energy Protocol Stack Basics
  3. 2The TI Bluetooth Low Energy Software Development Platform
    1. 2.1 Overview
    2. 2.2 Configurations
    3. 2.3 Projects
    4. 2.4 Software Overview
  4. 3The Operating System Abstraction Layer (OSAL)
    1. 3.1 Overview
    2. 3.2 Task Initialization
    3. 3.3 Task Events and Event Processing
    4. 3.4 Heap Manager
    5. 3.5 OSAL Messages
  5. 4The Application and Profiles
    1. 4.1 Overview
    2. 4.2 Project Overview
    3. 4.3 Start-up in main()
    4. 4.4 Application Initialization
    5. 4.5 Event Processing
      1. 4.5.1 Periodic Event
      2. 4.5.2 OSAL Messages
    6. 4.6 Callbacks
    7. 4.7 Complete Attribute Table
    8. 4.8 Additional Sample Projects
  6. 5The Bluetooth Low Energy Protocol Stack
    1. 5.1 Overview
    2. 5.2 Generic Access Profile (GAP)
      1. 5.2.1 Overview
        1. 5.2.1.1 Connection Parameters
        2. 5.2.1.2 Effective Connection Interval
        3. 5.2.1.3 Connection Parameter Considerations
        4. 5.2.1.4 Connection Parameter Update
        5. 5.2.1.5 Connection Termination
      2. 5.2.2 GAP Abstraction
      3. 5.2.3 Configuring the GAP Layer
    3. 5.3 GAPRole Task
      1. 5.3.1 Peripheral Role
      2. 5.3.2 Central Role
    4. 5.4 Gap Bond Manager (GAPBondMgr)
      1. 5.4.1 Overview of Bluetooth Low Energy Security
      2. 5.4.2 Using the GapBondMgr Profile
      3. 5.4.3 GAPBondMgr Examples for Various Security Modes
        1. 5.4.3.1 Pairing Disabled
        2. 5.4.3.2 Just Works Pairing Without Bonding
        3. 5.4.3.3 Just Works Pairing With Bonding Enabled
        4. 5.4.3.4 Authenticated Pairing
        5. 5.4.3.5 Authenticated Pairing With Bonding Enabled
    5. 5.5 Generic Attribute Profile (GATT)
      1. 5.5.1 GATT Characteristics and Attributes
      2. 5.5.2 GATT Services and Profile
      3. 5.5.3 GATT Client Abstraction
        1. 5.5.3.1 Using the GATT Layer Directly
      4. 5.5.4 GATT Server Abstraction
        1. 5.5.4.1 GATTServApp Module
          1. 5.5.4.1.1 Building Up the Attribute Table
        2. 5.5.4.2 Profile Architecture
          1. 5.5.4.2.1 Attribute Table Definition
            1. 5.5.4.2.1.1 Service Declaration
            2. 5.5.4.2.1.2 Characteristic Declaration
            3. 5.5.4.2.1.3 Characteristic Value
            4. 5.5.4.2.1.4 Client Characteristic Configuration
          2. 5.5.4.2.2 Add Service Function
          3. 5.5.4.2.3 Register Application Callback Function
          4. 5.5.4.2.4 Read and Write Callback Functions
            1. 5.5.4.2.4.1 Read Request from A GATT Client
            2. 5.5.4.2.4.2 Write Request From Client
          5. 5.5.4.2.5 Get and Set Functions
    6. 5.6 L2CAP
    7. 5.7 HCI
      1. 5.7.1 HCI Extension Vendor-Specific Commands
      2. 5.7.2 Receiving HCI Extension Events in the Application
    8. 5.8 Library Files
  7. 6Drivers
    1. 6.1  Overview
    2. 6.2  ADC
    3. 6.3  AES
    4. 6.4  LCD
    5. 6.5  LED
    6. 6.6  KEY
    7. 6.7  DMA
    8. 6.8  UART and SPI
    9. 6.9  Other Peripherals
    10. 6.10 Simple NV (SNV)
  8. 7Creating a Custom Bluetooth Low Energy Application
    1. 7.1 Overview
    2. 7.2 Configuring the Bluetooth Low Energy Stack
    3. 7.3 Define Bluetooth Low Energy Behavior
    4. 7.4 Define Application Tasks
    5. 7.5 Configure Hardware Peripherals
    6. 7.6 Configuring Parameters for Custom Hardware
      1. 7.6.1 Board File
      2. 7.6.2 Adjusting for 32-MHz Crystal Stabilization Time
      3. 7.6.3 Setting the Sleep Clock Accuracy
    7. 7.7 Software Considerations
      1. 7.7.1 Memory Management for GATT Notifications and Indications
      2. 7.7.2 Limit Application Processing During Bluetooth Low Energy Activity
      3. 7.7.3 Global Interrupts
  9. 8Development and Debugging
    1. 8.1 Overview
    2. 8.2 IAR Overview
    3. 8.3 Using IAR Embedded Workbench
      1. 8.3.1 Open an Existing Project
      2. 8.3.2 Project Options, Configurations, and Defined Symbols
      3. 8.3.3 Building and Debugging a Project
      4. 8.3.4 Linker Map File
  10. 9General Information
    1. 9.1 Overview
    2. 9.2 Porting From BLE-Stack 1.5.0 to 1.5.1
    3. 9.3 Porting From BLE-Stack 1.4.2 to 1.5.0
    4. 9.4 Porting From Earlier BLE-Stack Versions
      1. 9.4.1 Porting BLEv1.4.1 Projects to BLEv1.4.2
      2. 9.4.2 Porting BLEv1.4.0 Projects to BLEv1.4.1
        1. 9.4.2.1 Project Porting Directions
        2. 9.4.2.2 API Changes
        3. 9.4.2.3 Typedef Changes
        4. 9.4.2.4 Structure Changes
          1. 9.4.2.4.1 Array Elements Changed to Pointers
          2. 9.4.2.4.2 Additional Fields in Key Distribution Strucutre
        5. 9.4.2.5 Default Value of HAL Components
        6. 9.4.2.6 Allocating Memory for Over-the-Air Messages
        7. 9.4.2.7 Allocation of Client Characteristic Configuration Table
      3. 9.4.3 Porting BLEv1.3.2 Projects to BLEv1.4.0
      4. 9.4.4 Porting BLEv1.2 Projects to BLEv1.3
      5. 9.4.5 Porting From CC2540 to CC2541 Project
    5. 9.5 Release Notes History
    6. 9.6 Document History
  11.   A GAP API
    1.     A.1 Commands
    2.     A.2 Configurable Parameters
    3.     A.3 Events
  12.   B GAPRole Peripheral Role API
    1.     B.1 Commands
    2.     B.2 Configurable Parameters
    3.     B.3 Callbacks
      1.      B.3.1 State Change Callback (pfnStateChange)
      2.      B.3.2 RSSI Callback (pfnRssiRead)
  13.   C GAPRole Central Role API
    1.     C.1 Commands
    2.     C.2 Configurable Parameters
    3.     C.3 Callbacks
      1.      C.3.1 RSSI Callback (rssiCB)
      2.      C.3.2 Central Event Callback (eventCB)
  14.   D GATT/ATT API
    1.     D.1 Overview
    2.     D.2 Server Commands
    3.     D.3 Client Commands
    4.     D.4 Return Values
    5.     D.5 Events
    6.     D.6 GATT Commands and Corresponding ATT Events
    7.     D.7 ATT_ERROR_RSP Error Codes
  15.   E GATTServApp API
    1.     E.1 Overview
    2.     E.2 Commands
  16.   F GAPBondMgr API
    1.     F.1 Overview
    2.     F.2 Commands
    3.     F.3 Configurable Parameters
    4.     F.4 Callbacks
      1.      F.4.1 Passcode Callback (passcodeCB)
      2.      F.4.2 Pairing State Callback (pairStateCB)
  17.   G HCI Extension API
    1.     G.1 Overview
    2.     G.2 Commands
    3.     G.3 Host Error Codes
  18.   Revision History

7.6.2 Adjusting for 32-MHz Crystal Stabilization Time

Before entering sleep, the stack sets the sleep timer to wake before the next Bluetooth Low Energy event. The closer the wakeup is to the event, less power is wasted. If the wakeup is too close to the even, the sleep time might miss the event.

When the timer wakes, it must wait for the 32-MHz external crystal to stabilize. This stabilization time is affected by the inherent stabilization time of the crystal, how long the crystal has been off, the temperature, the voltage, and so forth. You must add a buffer to the wakeup time (that is, start earlier) to handle this variability in stabilization.

This buffer time is implemented using the HAL_SLEEP_ADJ_TICKS definition where the value of the definition corresponds to the number of 32-MHz ticks. This definition is set in hal_sleep.c to 25 for the CC2541 EM and 35 for the CC2540 EM by default. If the value of the definition is larger, the buffer time is longer and more power is wasted. Calculate this value empirically. If HAL_SLEEP_ADJ_TICKS is set too low, false advertisement restarts and connection drops occur. If these restarts and drops occur, increase the definition until they stop.