Version 1 (Anthony Rowe, 02/17/2007 09:44 am) → Version 2/13 (Anthony Rowe, 02/17/2007 09:45 am)

= Static Configuration (nrk_cfg.h) =

Given the memory constraints of embedded sensor operating systems, Nano-RK uses a
static design-time framework. This approach is consistent with sensor networking assumptions
because as compared to traditional operating systems (where processes can
be dynamically spawned), the OS and the applications are co-located in a single address
space. In particular, admission control and real-time schedulability analysis tests
are carried out offline as compared to taking a dynamic online approach. We would
like to stress that a static approach does not mean that task properties and configuration
parameters cannot be reconfigured during run-time. Rather, a static approach enforces
the checks to ensure that the dynamic reconfiguration does not adversely affect application
and system guarantees in a pre-deployment offline setting as compared to running
dynamic admission control algorithms. Data (or control) dependent modifications to
the task code such as changing task periods, resource usage limits, resource priorities
and configuration of various parameters such as the network buffer sizes and stack
sizes of each task can be changed to accommodate mode changes. With current energy
and memory constraints, the run-time configurations will need to be verified offline at

Many of the static parameters are defined in nrk_cfg.h

// NRK_REPORT_ERRORS will cause the kernel to print out information about
// missed deadlines or reserve violations

// NRK_HALT_ON_ERRORS will cause the kernel to freeze on errors so that
// it is easier to see debugging messages.

// NRK_STACK_CHECK adds a little check to see if the bottom of the stack
// has been over written on all suspend calls

// Leave NRK_NO_POWER_DOWN define in if the target can not wake up from sleep
// because it has no asynchronously clocked

#define NRK_MAX_TASKS 2
// Max number of tasks in your application

#define NRK_N_SYS_TASKS 1
// Number of system tasks. You need at least the idle task

// Idle task stack size min=32
// Used as a default for application tasks
// Size of kernel stack

A sample nrk_cfg.h that configures the static parameters for a particular
project. This includes stack sizes, number of resources, error handling etc.
Make sure tomake clean when you change any parameters in header files
or moved from another project directory.

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