6.3.6.2 OTA Application Development

This section provides a comprehensive guide for compiling and integrating the MCC auto-generated BLE OTA project, including mandatory user edits, event handler integration, timer configuration, and .bin file generation for OTA updates.

Open and compile the project generated by MCC.
1. Click Build the Porject (hammer symbol).
  Figure 6-59. Build the Project
  
  Figure 6-60. Build Fail Message
2. If the user encounters a mandatory error in app_user_edits.c, follow the instructions in the note within the file. Make the required changes, then comment out the #error directive to proceed.
  
  Figure 6-61. #Error: User Action Required

In app.c, within the APP_Tasks() function, call APP_Init() when the state is APP_STATE_INIT.

#include "ble_dis/ble_dis.h"
#include "app_ble_conn_handler.h"
#include "app_ble_sensor.h"
#include "app_adv.h"
#include "system/console/sys_console.h"
#include "ble_otaps/ble_otaps.h"
#include "app_ota/app_ota_handler.h"
uint32_t wbz451_silicon_revision = 0x00;
static void APP_Init(void)
{
    APP_BleStackInit();

    /* Add BLE Service */
    BLE_DIS_Add();

    APP_UpdateLocalName(0, NULL);
    APP_InitConnList();
    APP_ADV_Init();
    
    SYS_CONSOLE_MESSAGE("BLE Sensor Application: Version ");
    SYS_CONSOLE_PRINT(BLE_SENSOR_VERSION);
    SYS_CONSOLE_MESSAGE("\n\r[BLE} Advertisement Started\n\r");    

    APP_TRPS_Sensor_Init();
    
    APP_OTA_HDL_Init();
    
    wbz451_silicon_revision = 	DSU_REGS->DSU_DID;	
    SYS_CONSOLE_PRINT("\n\r[Device DID] 0x%x  \n\r", (DSU_REGS->DSU_DID)); 
    
    if(wbz451_silicon_revision & (1 << 29)) // A2 Silicon // if((wbz451_silicon_revision >> 28) == (0x02))
    {  
          /* PPS Output Remapping */
      PPS_REGS->PPS_RPB0G1R = 11U;
      PPS_REGS->PPS_RPB3G4R = 12U;
      PPS_REGS->PPS_RPB5G3R = 11U;
    }
    else if((wbz451_silicon_revision >> 28) ==  (0x00)) // A0 silicon
    {
      /* PPS Output Remapping */
      PPS_REGS->PPS_RPB0G1R = 21U;
      PPS_REGS->PPS_RPB3G4R = 21U;
      PPS_REGS->PPS_RPB5G3R = 22U;
    }	
}

In app_ble/app_otaps_handler.c, call the BLE OTA event handler function to manage OTA events.
- The user can call the function to process OTA events during run-time by invoking the appropriate handler.
```
APP_OTA_EvtHandler(p_event);
```
- The user can use this #include directive to make the OTA handler functions and definitions available in the source file.
```
#include "../app_ota/app_ota_handler.h"
```
Figure 6-63. Application OTA Handler (Header File)
In app_timer/app_timer.c, uncomment the timer message IDs needed for OTA error handling and reboot timer. When the timer fires, post the related message to the FreeRTOS application task queue.

Figure 6-64. app_timer/app_timer.c: Timer Expiry Handler Posting OTA and Reboot Messages

Figure 6-65. Periodic Timer Expired Handle
In the APP_MsgId_T structure in app.h, define the following message IDs:
```
APP_TIMER_ADV_CTRL_MSG,    
APP_TIMER_BLE_SENSOR_MSG,
APP_MSG_TRS_BLE_SENSOR_INT,
APP_TIMER_OTA_TIMEOUT_MSG,
APP_TIMER_OTA_REBOOT_MSG,
```
Figure 6-66. Application Message Identifier Type (APP_MsgID_T)

In app.c, within the APP_Tasks() function, handle the timer messages by calling the appropriate handler functions:

else if(p_appMsg->msgId== APP_TIMER_ADV_CTRL_MSG)
{
APP_BLE_Adv_TimerHandler();
}
else if(p_appMsg->msgId== APP_TIMER_BLE_SENSOR_MSG)
{
APP_TRPS_Sensor_TimerHandler();
}
else if(p_appMsg->msgId== APP_MSG_TRS_BLE_SENSOR_INT)
{
APP_TRPS_Sensor_Button_Handler(); 
}               
else if(p_appMsg->msgId == APP_TIMER_OTA_TIMEOUT_MSG)
{
APP_OTA_Timeout_Handler(); 
}
else if(p_appMsg->msgId== APP_TIMER_OTA_REBOOT_MSG)
{
APP_OTA_Reboot_Handler(); 
}

Figure 6-67. Application Timer Advertisement Control Message

In app_ble/app_ble_handler.c, call the BLE GAP connected/disconnected event handler. In app_ble_conn_handler.c, handle these events and restart advertising when disconnected.
- The user can call the function to process BLE GAP connection events during run-time by invoking the appropriate handler.
```
APP_BleGapConnEvtHandler(p_event);
```
- The user can use the #include directive to make the BLE connection handler functions and definitions available in the source file.
```
#include "../app_ble_conn_handler.h"
```
Figure 6-68. System Console Operations and BLE Connection Handler

Figure 6-69. BLE_GAP Connection Event Handler

Figure 6-70. BLE Security Manager Protocol Event Handler
In APP_BleGapConnEvtHandler() in app_ble_conn_handler.c, add print statements to the console for debugging and status updates.

Figure 6-71. BLE Connection Establishment and Device Info Update
If low power (Standby Sleep) mode is enabled, prevent the device from entering sleep during OTA upgrades. In app_idle_task(), add a check before calling BT_SYS_EnterSleepMode(), using the OTA handler include:
```
#include "app_ota/app_ota_handler.h"

if (APP_OTA_HDL_GetOTAMode() != APP_OTA_MODE_OTA)
{
    BT_SYS_EnterSleepMode(RTC_Timer32FrequencyGet(), RTC_Timer32CounterGet());
}
```
Figure 6-72. Application OTA Handler Get OTA Mode
In app_idle_task.c, modify vPortSuppressTicksAndSleep().
- Add the required code to manage sleep behavior during OTA in the FreeRTOS tickless idle function.
Figure 6-73. Tickless Idle Mode Implementation
In app_ota-handler.c, comment out the s_fwImageValidate value as per the application needs.

Figure 6-74. OTA Firmware Image Type and CRC Validation Logic
In app_trsps_handler.c, implement code for handling BLE_TRSPS_EVT_CTRL_STATUS and BLE_TRSPS_EVT_VENDOR_CMD events.

Figure 6-75. TRSPS Control Status and Vendor Command Event Handling

In app_ble_conn_handler.c, handle the BLE_GAP_EVT_DISCONNECTED event and include the following files:

#include "app_timer/app_timer.h"
#include "app_adv.h"
#include "app_trps.h"
#include "app_ble_sensor.h"
#include "peripheral/gpio/plib_gpio.h"
#include "system/console/sys_console.h"

Build the project and ensure there are no errors.
Figure 6-77. Build the Project

For more details on the OTA Profile Middleware API’s, refer to the MPLAB Harmony Wireless BLE in the Reference Documentation from Related Links.

For more details on OTA Application Level API’s, see BLE_OTA from Related Links.