Class B solution structure

AN3307

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Doc ID 18186 Rev 4

measurement to be performed in the SysTick interrupt service routine. The

SysTick_Handler() interrupt service counts ticks and performs short partial transparent

RAM March C or March X checks at correct intervals (20 ms) when a flag (TimeBaseFlag) is

set to synchronize the rest of the runtime checks called from the main level. The

FailSafePOR() routine itself is described in Section 4.1.1: Fail Safe mode.

5.2

Description of startup self tests

The startup self-tests should be run during the initialization phase as the first check

performed after resetting the micro (see Figure 5). This is done by forcing the reset vector to

the address the start of the STL_StartUp() routine. The structure of the block of startup

tests structure is shown in Figure 6 and it includes the following self tests:

●

CPU startup test

●

Watchdog startup tests

●

Flash complete checksum test

●

Full RAM March C/X test

●

Clock startup test

●

Control flow check

These blocks are described in more detail further in this section.

Figure 6.

Startup self tests structure

MS18593V1

RESET

Watchdogs self-test

Switch PLL ON

Flash integrity check

RAM functional check

Clock frequency check

Control Flow check

Resume C startup

Fail Safe routine

Fail

Fail

Fail

Fail

HW Reset

CPU core self-test

Fail

Switch PLL Off