Case 语句中的数组

Question

我在将数组用于状态机的 case 语句时遇到问题。大多数网站都提到数组不能用于 case 语句，所以我一直在尝试解决它，但到目前为止它一直没有成功。我真的很感激任何帮助或建议。 澄清：我不想对状态进行硬编码，我试图以这样一种方式制作程序，即如果用户只更改 fsm_state_array[] 中的顺序，程序将在其中执行仅订购而不更改 void loop() 中的任何其他内容。

这是我到目前为止所尝试的，当用户在数组中输入他们的状态序列时，我使用函数来硬编码来检查前一个状态、当前状态和下一个状态，所以在我下面的代码中，状态应该去从 0 --> 2 --> 3--> 1 ，但是，我得到 0 --> 2 --> 1 --> 3。我知道如果我只在案例中使用数组，这个问题很容易解决声明，但编译器给了我一个错误。对于这方面的任何帮助或建议，我将不胜感激。

我的代码如下所示：

//Objectives: Use input from laser to control pre-amp on adc. Multiplex the inputs on Pre-Amp
//Type: Pulse, Freq:20Hz (50ms), Amp:5.0 Vpp, Offset:500mV, Width = 100ns

//-----------------------PROJECT LIBRARIES----------------------------------
#include <Bounce2.h>
#include <Arduino.h>
#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
//-----------------------DEFINES------------------------------------------
//Declare Laser Input Pin
#define LASER_PIN 2

//Declare Reset Pin
#define RESET_PIN 3


typedef enum {
  STATE_0,
  STATE_1,
  STATE_2,
  STATE_3
} fsm_state;

//User can change or remove states here
fsm_state fsm_state_Array[] = {STATE_0, STATE_2, STATE_3, STATE_1};

 //*eNextstate controls on which state the program starts the state machine, default is STATE_00, Must be same value as Transition_State[0]
fsm_state eNextState = fsm_state_Array[0];

int Current_State = 0;
int Next_State = 0;
int Previous_State = 0;

// -------------------------CONSTANTS (won't change)-------------------------------------
const unsigned long period = 1000;  //the value is a number of milliseconds

//-------------------------VARIABLES (will change)-------------------------------------
bool only_for_print = false;//used only for print state ments

int reset_switch = 1;//Start HIGH to avoid reset
int PulseCount = 0; //Pulse count from X-RAY
int Output = 0;//Switch state on the Pre-Amp
int wait = 0;//wait for pulses count
int N = 20;//no. of pulses to count before switching states
volatile int IRQcount = 0;
volatile boolean reset_flag = false;

unsigned long start_time = 0;
unsigned long current_time = 0;

//----------------------------USER DEFINED FUNCTIONS---------------------------------
void fsm();
void loop();
void setup();
void WDT_RESET();
void IRQcounter();
void CountPulses();
//-----------------------------DEBOUNCE FUNCTIONS---------------------------------------


//--------------------------------MAIN SETUP--------------------------------------

void setup()
{

  Serial.begin(115200);
  //Pin Setup
  pinMode(LASER_PIN, INPUT_PULLUP);
  pinMode(RESET_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(LASER_PIN), IRQcounter, RISING);//attach interrupt handler to laser input
  attachInterrupt (digitalPinToInterrupt (RESET_PIN), RESET_ISR, FALLING);  // attach interrupt handler to reset, wait for user press button or switch
  start_time = millis();   //initial start time
  sei();//Turn on Interrupts

  WaitForPulses();//Waits to detect 20 pulses
}

//--------------------------------MAIN LOOP----------------------------------
void loop()
{


  current_time = millis();
  fsm();//State machine
}


//--------------------------------PULSE COUNT FUNCTION--------------------------------------------



void CountPulses()
{
  //  current_time = millis();
  if ((current_time - start_time) >= period)
  {
    start_time = current_time;
    cli();//disable interrupts
    PulseCount = IRQcount;
    IRQcount = 0;
    Serial.print(F("Pulse Count is = "));
    Serial.println(PulseCount);
    sei();//enable interrupts
  }
}

//--------------------------------STATE MACHINE FUNCTION--------------------------------------------
void fsm()
{
  switch (eNextState)
  {



    case STATE_0:

      /////////Print Statement only for debugging//////////
      while (only_for_print == false)
      {
        Serial.println("The state is 0");
        only_for_print = true;
      }  

      ///////// Count Pulses Setup /////////////////
        Previous_State = fsm_state_Array[3];
        Current_State= 0;
        Next_State = fsm_state_Array[1];


        current_time = millis();
        CountPulses();
        Output = 0;

      if (PulseCount == N)
      {
        PulseCount = 0;//Reset Pulse Count
        only_for_print = false; //used only for print statments
       State_Check_0_to_1();//Move to next state
      }
      break;


    case STATE_1:
      /////////Print Statement only for debugging//////////
      while (only_for_print == false)
      {
        Serial.println("The state is 1");
        only_for_print = true;
      }

      ///////// Count Pulses Setup /////////////////

       Previous_State = fsm_state_Array[0];
        Current_State= 1;
        Next_State = fsm_state_Array[2];

      current_time = millis();
      CountPulses();
      Output = 1;
      if (PulseCount == N)
      {
        PulseCount = 0;//Reset Pulse Count
        only_for_print = false; //used only for print statments
        State_Check_1_to_2();//Move to next state
      }
      break;


    case STATE_2:
      /////////Print Statement only for debugging//////////
      while (only_for_print == false)
      {
        Serial.println("The state is 2");
        only_for_print = true;
      }

      ///////// Count Pulses Setup /////////////////

         Previous_State = fsm_state_Array[1];
        Current_State= 2;
        Next_State = fsm_state_Array[3];


      current_time = millis();
      CountPulses();
      Output = 2;
      if (PulseCount == N)
      {
        PulseCount = 0;//Reset Pulse Count
        only_for_print = false; //used only for print statments
        State_Check_2_to_3();//Move to next state
      }

      break;


    case STATE_3:
      /////////Print Statement only for debugging//////////
      while (only_for_print == false)
      {
        Serial.println("The state is 3");
        only_for_print = true;
      }
      ///////// Count Pulses Setup /////////////////

       Previous_State = fsm_state_Array[2];
       Current_State= 3;
       Next_State = fsm_state_Array[0];

      current_time = millis();
      CountPulses();
      Output = 3;
      if (PulseCount == N)
      {
        PulseCount = 0;//Reset Pulse Count
        only_for_print = false; //used only for print statments
       State_Check_3_to_0();//Move to next state
      }

      break;


  }

}

//----------------------------------RESET SWITCH ISR-------------------------------------

void RESET_ISR()
{
  reset_flag = true;
  if (reset_flag == true)
  {
    // Serial.println("System will now Reset");// Only for debugging
    reset_flag = false;//Reset reset switch flag
    wdt_enable(WDTO_500MS);//Reset after 0.5 seconds
    while (1)
    {
      // wdt_reset();          // uncomment to avoid reboot
    }
  }
}


//-----------------------PULSE COUNT ISR---------------------------------------

void IRQcounter()
{
  IRQcount++;
}
//-----------------------WAIT FOR PULSES---------------------------------------
void WaitForPulses()
{
  while (wait < 20)
  {
    if (bit_is_set(EIFR, INTF0))
    {
      Serial.println("Pulse is detected ");
      wait++;
    }
  }
  wait = 0;//reset
}

void State_Check_0_to_1()//Check values of state 0 before going to state 1 
{

    if(Previous_State == fsm_state_Array[3] && Current_State == 0 && Next_State == fsm_state_Array[1])
    {
      eNextState = Next_State;
    }


}

void State_Check_1_to_2()//Check values of state 1 before going to state 2 
{

    if((Previous_State == fsm_state_Array[0]) && (Current_State == 1) && (Next_State == fsm_state_Array[2]))
    {
      eNextState = Next_State;

    }

}


void State_Check_2_to_3()//Check values of state 2 before going to state 3 
{

    if((Previous_State == fsm_state_Array[1]) && (Current_State == 2) && (Next_State == fsm_state_Array[3]))
    {
      eNextState = Next_State;

    }

}


void State_Check_3_to_0()//Check values of state 3 before going to state 0 
{

    if((Previous_State == fsm_state_Array[2]) && (Current_State == 3) && (Next_State == fsm_state_Array[0]))
    {
      eNextState = Next_State;

    }

}

这是我的串行监视器显示的内容：

Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
Pulse is detected
The state is 0                               -----> State 0
Pulse Count is = 72
Pulse Count is = 19
Pulse Count is = 20
The state is 2                               -----> State 2
Pulse Count is = 20
The state is 1                               -----> State 1
Pulse Count is = 21
Pulse Count is = 19
Pulse Count is = 21
Pulse Count is = 19
Pulse Count is = 21
Pulse Count is = 19
Pulse Count is = 21
Pulse Count is = 19
Pulse Count is = 21
Pulse Count is = 20
The state is 3                           -----> State 3
Pulse Count is = 20
The state is 0       
Pulse Count is = 20
The state is 2
Pulse Count is = 20
The state is 1
Pulse Count is = 20
The state is 3

使用 cmets 中建议的指针测试 FSM 的单独代码：

typedef void (*current_state)();
void state0();
void state1();
void state2();
void state3();
current_state states[4]={&state0,&state2,&state3,&state1};
current_state next_state;
void setup() 
{
 Serial.begin(115200);

}

void loop()
{
  current_state();
}


void state0() 
{
   next_state = states[1]; // No parenthesis!
   Serial.println("I am in STATE 0");
}
void state1() 
{
   next_state = states[2]; // No parenthesis!
   Serial.println("I am in STATE 1");
}
void state2() 
{
   next_state = states[3]; // No parenthesis!
   Serial.println("I am in STATE 2");
}
void state3() 
{
   next_state = states[0]; // No parenthesis!
   Serial.println("I am in STATE 3");
}

Answer 1

这段代码来自处理STATE_2

Next_State = fsm_state_Array[3];

将Next_State 设置为STATE_1，因为数组初始化为

fsm_state fsm_state_Array[] = {STATE_0, STATE_2, STATE_3, STATE_1};

也就是说……

fsm_state_Array[0] = STATE_0;
fsm_state_Array[1] = STATE_2;
fsm_state_Array[2] = STATE_3;
fsm_state_Array[3] = STATE_1;  // This is the element used

为了提供更“动态”的解决方案，可能使用函数指针表示状态比使用开关效果更好：

// Current state is just a apointer to a void function
// accepting no parameters
void (*current_state)();

// All states are just void functions accepting no parameters
void state1();
void state2();
...

// To set what is the next state you update current_state
void state1() {
   ...
   current_state = state2; // No parenthesis!
}


// In the main handler you just call current_state

...
current_state(); // Do the state processing

如果你想执行一系列操作，那么使用函数指针你可以保留一个数组并对其进行迭代：

void (*states[])() = {
    state1,
    state2,
    state3,
    ...
    NULL       /// To mark the end of the sequence
};

然后你可以按顺序执行这些步骤

void main() {
    for(int i=0; states[i]; i++) {
        states[i](); // Execute the step
    }
}