AN3307

Class B solution structure

Doc ID 18186 Rev 4

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5

Class B solution structure

5.1

Integrating the software into the user application

Class B routines are divided into two main processes: startup and periodic runtime self

tests. The periodic runtime test must be initialized by a set-up block before it is applied. All

the processes are covered by adequate caller-called controls checked at a number of flow

check points. All class B variables are kept redundantly in duplicate control registers stored

in user-defined Class B variable space. This space is split into two separate RAM regions

which are under permanent control of a transparent test which is part of the runtime tests.

Figure 5 shows the basic principle of how to integrate the Class B software package into a

user software solution. The reset vector should be forced by the user to jump to the

STL_StartUp() procedure which contains all the system self tests to be performed at

startup. If all these tests pass sucessfully then the standard startup procedure

__iar_program_start() for IAR or Reset_Handler() for the KEIL solution is performed.

Figure 5.

Integration of startup and periodic runtime self-tests into the application

While the application is running, periodic tests are performed at certain intervals. To run

them, users must execute an initialization block by calling STL_InitRunTimeChecks()

routine in the initialization phase and then insert a periodic call to

STL_DoRunTimeChecks() at the main level, preferably in the main loop. Periodic system

interrupts are configured by initializing the SysTick clock frequency and themain time base

measurement in the initial routine. The RTC is also reset and synchronized to allow

RESET

Start up self-test

(STL _StartUp ())

Application startup

Periodic runtime self-test init

(STL_InitRunTimeChecks())

Main loop

Task 1

Task 2

Task 3

Timebase ISR

ISR 1

ISR 2

Fail Safe routine

(FailSafePOR())

MS18592V2

Periodic runtime self-test

(STL_DoRunTimeChecks())

(SysTick_Handler())