1. Startup and Initialization
Development Basics
Startup and Initialization
Power on board
Start (crt0) - executes at power up
Board initialization
Operating System Initialization
Application Program Initialization
Start Scheduler
Execute start code
Initialize board
Operating sys init
Application Initialize
Start Scheduler

2. Generally used to control access to a “shared resource”
Task Synchronization
Binary Semaphores
Generally used to control access to a “shared resource”
Program Execution
Obtain Semaphore
Shared
Resource
Release Semaphore

3. Critical Sections / Reentrancy
Interrupt
Disable Interrupts
Critical Section
Enable Interrupts

4. Creation and Deletion of Objects
Control Block - required for every object; you define location anywhere in memory
Memory Requirements - data needed for components (e.g., task stack, queue space, etc.)

5. Source File Structure Component Source Code
XX_DEFS.H - component constants and data structures
XX_EXTR.H - external interfaces (function prototypes)
XX_D.C - static and global data structure definitions
XX_I.C - initialization functions for component
XX_F.C - status functions for component
XX_C.C - core functions for component
XX_CE.C - error checking shell functions of core functions
XX_S.C - supplemental functions for component
XX_SE.C - error checking shell functions for supplemental functions

6. System Startup Startup Vector INT_Initialize() INC_Initialize()
Nucleus Services Init
Application_Initialize()
TCT_Schedule()

7. System Startup Application Memory .code .data (initialized data)
.bss (uninitialized data)
first_available_memory_address
application memory

8. System Startup
Code
INT_Initialize - contains target processor dependent initialization routines and data.
Setup necessary processor/system control registers
Setup system stack
Setup timer interrupt
Calculate timer HISR stack and priority
Calculate first available memory address
Transfer control to INC_Initialize()

9. System Startup INC_Initialize( ) Nucleus PLUS Component Initialization
Code
INC_Initialize( )
Nucleus PLUS Component Initialization
Initialization of Error Handling, History, Thread Control, Mailbox, Queue, Pipe, Semaphore, Event Group, Partition Memory, Dynamic Memory, Timer, and I/O Driver Components
Application_Initialize()
TCT_Schedule()

10. System Startup Application_Initialize( ) Create dynamic memory pool
Code
Application_Initialize( )
Create dynamic memory pool
NU_Create_Memory_Pool( )
Create Tasks
NU_Allocate_Memory( )
NU_Create_Task( )
Create other system objects (optional)
NU_Create_Queue( )
NU_Create_Semaphore( ) …
NOTE - Interrupts disabled during Application_Initialize( )

11. System Startup Application Memory .code .data (initialized data)
.bss (uninitialized data)
System stack
Timer HISR stack
first_available_memory_address
application memory

12. Critical Sections / Reentrancy
Protection
Protection - “monitor” surrounding Nucleus PLUS service calls
prevents disabling of interrupts
prevents priority inversion
NU_Unprotect
NU_Protect