Simplified state transition program

This post introduces compact state transition programs.

Embedded products are increasingly equipped with anomaly detection and fail-safe functions to meet functional safety and other standards. Some products have more than 100 anomaly detections, and many of these anomaly detection information (state transition conditions: events) may result in a large state transition program. Therefore, we introduce a compact state transition program.

Feature

• Places events in the bitfields of state variables.
• Calls state applications from the value of a state variable without determining the state from the event.
• Replaces label names to match specifications, ensuring consistency with specifications.

typedef struct{
        union{
                unsigned char state;
                struct{
                        unsigned char b7 : 1;
                        unsigned char b6 : 1;
                        unsigned char b5 : 1;
                        unsigned char b4 : 1;
                        unsigned char b3 : 1;
                        unsigned char b2 : 1;
                        unsigned char b1 : 1;
                        unsigned char b0 : 1;
                }event;
        };
}state_event;

static state_event STATE[3] = { { .state = 0x80 }, { .state = 0U }, { .state = 0U } };

// Re Lable name
#define State1  STATE[0].state
#define State2  STATE[1].state
#define State3  STATE[2].state
#define E1      State2.event.b7
#define E2      State2.event.b6
#define E3      State1.event.b7
#define E4      State3.event.b7
#define E5      State3.event.b6
#define E6      State3.event.b5
#define E7      State3.event.b4
#define E8      State1.event.b6

void Func_State1( void );
void Func_State2( void );
void Func_State3( void );

void Func_state_flow( void )
{
        if( State1 !=0 ){
                Func_State1();
        }else if( State2 != 0 ){
                Func_State2();
        }else if( State3 != 0 ){
                Func_State3();
        }else{
                // State flow Error
        }
}

void Func_State1( void )
{
        // State1 Application
        // E1, E2, E6, E7 Judgment
}

void Func_State2( void )
{
        // State2 Application
        // E3, E4, E5 Judgment
}

void Func_State3( void )
{
        // State3 Application
        // E8 Judgment
}