3.1.2.4 BLE Deep Sleep Advertising

Introduction

This document will help users to enable Deep sleep mode with BLE Advertisements on WBZ451 Curiosity board using MPLAB Code Configurator(MCC). In this basic application example, the Deep Sleep advertisement interval will be set to 960 millisecond. The advertisement interval will dictate the application Deep sleep time.

Users can choose to just run the precompiled Application Example hex file on the WBZ451 Curiosity Board and experience the demo or can go through the steps involved in developing this Application from scratch.

It is recommend to follow the examples in order, by learning the basic concepts first and then progressing to the more advanced topics.

Recommended Reading

Hardware Requirement

SDK Setup

Software Requirement

Smartphone App

Programming the precompiled hex file or Application Example

Programming the hex file using MPLABX IPE

1. Precompiled Hex file is located in "<Harmony Content Path>\wireless_apps_pic32cxbz2_wbz45\apps\ble\building_blocks\peripheral\deep_sleep_adv\hex" folder

2. For the instructions, refer to Programming A Device.

   Note: Users must choose the correct Device and Tool information.

Programming the Application using MPLABX IDE

1. Follow the steps mentioned in Running a Precompiled Example .

2. Open and program the Application Example "ble_deep_sleep_adv.x" located in "<Harmony Content Path>\wireless_apps_pic32cxbz2_wbz45\apps\ble\building_blocks\peripheral\deep_sleep_adv\firmware" using MPLABX IDE

For more details on how to find the Harmony Content Path, refer to Installing MCC Plugin

Demo Description

This Application Example enables users to enter Deep sleep mode while transmitting Connectable, Undirected BLE Advertisements. On power on reset demo will enter "Deep Sleep Mode", when the USR_BTN(SW2) is pressed the device onboard led(green) starts blinking which denotes start of advertisements, Device will enter Deep sleep mode periodically based on the advertisement interval which is set to 960 milliseconds for this example. When device connects with the mobile App the onboard led start to glow solid, which indicates the connection established and the device will enter Standby Sleep Mode during Idle state.

Testing

Connect the WBZ451 Curiosity board to PC, program the precompiled hex file or application example as mentioned. Upon flashing, there will not be any indication on the board, since the device enters deep sleep mode. User can press the USR_BTN(SW2) available on the board to start Deep sleep Advertising. To connect to the WBZ451, User can open the Light Blue App on Smartphone to scan for Advertisements. Device name "BLE_DSADV" will appear.

Current Consumption Measurement

Connect the Multimeter/Power Debugger to Power Measurement Header J6. Power on the Board. If using Power Debugger, users can use Data Visualizer to measure the current consumption.

Current measured in Deep sleep mode as per Wireless_ble v 1.1.0 and Wireless_pic32cxbz_wbz v1.2.0 in A2 version of WBZ451 module is around 1.21 uA.

Users of this Early adopter package must go through the known issues document and understand the limitations if any with the current low power mode implementation.

Developing this Application from scratch using MPLAB Code Configurator

Verifying Deep Sleep, Advertisement, System Sleep and RTC Clock Source Configuration

Generating a Code

Follow the instructions on how to generate a code, as described in 14.2 MPLAB Code Configurator(MCC) Code Generation.

After generating the program source from MCC interface by clicking Generate Code, the BLE configuration can be found in the following project directories.

The OSAL, RF System, BLE System initialization routine executed during program initialization can be found in the project files. This initialization routine is automatically generated by the MCC.

The BLE stack initialization routine excuted during Application Initialization can be found in project files. This intitialization routine is automatically generated by the MCC. This call initializes and configures the GAP, GATT, SMP, L2CAP and BLE middleware layers.

During system sleep, clock (system PLL) will be disabled and system tick will be turned off. FreeRTOS timer needs to be componsated for the time spent in sleep. RTC timer which works in the sleep mode is used to accomplish this. RTC timer will be initialized after BLE stack initialization.

Header Files

• ble_gap.h: This header file contains BLE GAP functions and is automatically included in the app.c file

Function Calls

• APP_BleStackInit() and APP_BleDsadvStart(flag) are the API's that will be called inside the Applications Initial State -- APP_STATE_INIT in app.c.

System Manual Configurations

The following code modifications must be done to utilize the deep sleep Advertising functionality.

Step 1 - Initialization.c

• CLK_Initialize();
  This API call will be originally available in SYS_Initialize function and should be called part of _on_reset() function inside initialization.c file.

  

• void SYS_Initialize (void* data)

  The below generated code should be removed from the SYS_Initialize Function.

  

  Add the below code inside SYS_Initialize Function.

  DEVICE_DeepSleepWakeSrc_T wakeSrc;
  DEVICE_GetDeepSleepWakeUpSrc(&wakeSrc);
  if (wakeSrc == DEVICE_DEEP_SLEEP_WAKE_NONE) //Initialize RTC if wake source is none(i.e power on reset)
  {
   RTC_Initialize();
  }

  

  Step 2 - startup_xc32.c

  • PCHE_SetupRam()

    Copy the below code into the startup_xc32.c

    __attribute__((ramfunc, long_call, section(".ramfunc"),unique_section)) void PCHE_SetupRam(void)
    {
      // Set Flash Wait states and enable pre-fetch
      // clear PFMWS and ADRWS
      PCHE_REGS->PCHE_CHECON = (PCHE_REGS->PCHE_CHECON & (~(PCHE_CHECON_PFMWS_Msk | PCHE_CHECON_ADRWS_Msk | PCHE_CHECON_PREFEN_Msk)))
                                      | (PCHE_CHECON_PFMWS(1) | PCHE_CHECON_PREFEN(1));
     
      // write completion delay
      for(int i=1; i<10; i++)
      {
          asm ("NOP");
      }
    }

    

    Copy the below code into the Reset_Handler Handler Function after __pic32c_data_initialization() Function Call.

    if (!(DSU_REGS->DSU_DID & DSU_DID_REVISION_Msk))   //HW A0 version
       {
           PCHE_SetupRam();
       }

    

    Step 3 - heap_4.c

    Modify with the following code inside heap_4.c (available as part of FreeRTOS-->MemMang)

    static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ]; --> Original Code
     
    static uint8_t  __attribute__((section (".bss.ucHeap"), noload)) ucHeap[ configTOTAL_HEAP_SIZE ]; -->Modified Code

    

    Step 4 - device_deep_sleep.c(optional)

    Configure the peripheral ports to minimize the current consumption. Those configurations must be placed in the function “Device_GpioConfig”.
    According to WBZ451 curiosity board pins assignment, the function provides example code to setup the GPIO pins and the peripheral. To setup the board configuration, refer to the configuration examples.

    

    The “Device_GpioConfig” is inside “DEVICE_EnterDeepSleep” to enter Deep sleep.

    

User Application Development

Include

Enter Deep Sleep mode

• DEVICE_EnterDeepSleep(false,0);

  This API can be called to put the device to deep sleep mode.

Start Deep Sleep Advertisement

• APP_BleDsadvStart(false);

  This API can be called to start the Deep sleep Advertising.

  This API is called in the Applications initialstate - APP_STATE_INIT in app.c

  

  Users can exercise various other BLE Advertisement functionalities by using BLE Stack API.