マイコン(Master)とZynq(Slave)をI2C通信する方法 (4)マイコンのソフトウェア構成(arduino)

#include "Wire.h"

int   state;
int   count;
enum StateType{
  STATE_WAIT,
  STATE_READ,
  STATE_WRITE,
  STATE_IDLE
};

#define ZYNQ_ADDR 0x45
#define IIC_SCLK_RATE    400000
#define DATA_NUM 250
 
void setup() {
    Wire.begin(ZYNQ_ADDR);        // join i2c0 bus (pin #3,5)
    Wire.setClock(IIC_SCLK_RATE);
    
    Serial.begin(9600);  // start serial for output
    state = STATE_WAIT;
}

void loop() {
    char  buf[DATA_NUM];
    char  c;
    int   ret;

    switch (state){
        case STATE_WAIT:
            Serial.print("----------------------------\n");
            Serial.print("Request message from wio to zynq\n");
            
            Wire.requestFrom(ZYNQ_ADDR, DATA_NUM);
            delay(500);
            
            if(Wire.available() > 0){
              state = STATE_READ;
              Serial.print("Read from zynq to wio\n");
              count = 0;
            }else{
              state = state;
            }
            
            break;
        case STATE_READ:
            if(count == DATA_NUM){
              Serial.print("read finish!\n");
              Serial.print("----------------------------\n"); 
              Serial.print("Write from wio to zynq\n");
              
              state = STATE_WRITE;
              count = 0;
            }else if( count < DATA_NUM ){
              c = Wire.read(); // receive one byte as characterif
              buf[count] = c;
              Serial.print((int)(buf[count]));
              Serial.print(",");

              state = state;
              count++;
            }
            
            break;
        case STATE_WRITE:
            Wire.beginTransmission(ZYNQ_ADDR); // transmit to device #4
            Wire.write(buf, 250);              // send to zynq  
            ret = Wire.endTransmission();    // stop transmitting
            
            if(ret == 0){
              Serial.print("write finish!\n");
              Serial.print("----------------------------\n");
              
              state = STATE_IDLE;
            }else{
              if(ret == 1){Serial.print("Error 01: Data length exceeds to buffer length!\n");}
              else if(ret == 2){Serial.print("Error 02: No response to address send!\n");}
              else if(ret == 3){Serial.print("Error 03: No response to data send!\n");}
              else if(ret == 4){Serial.print("Error 04: others\n");}
              
              state = state;
            }
            
            break;
        case STATE_IDLE:
            state = state;
            break;
        default:
            state = state;
            break;
    }
}

        case STATE_WAIT:
            Serial.print("----------------------------\n");
            Serial.print("Request message from wio to zynq\n");
            
            Wire.requestFrom(ZYNQ_ADDR, DATA_NUM);
            delay(500);
            
            if(Wire.available() > 0){
              state = STATE_READ;
              Serial.print("Read from zynq to wio\n");
              count = 0;
            }else{
              state = state;
            }
            
            break;

              Serial.print((int)(buf[count]));
              Serial.print(",");

              Serial.print("read finish!\n");
              Serial.print("----------------------------\n"); 
              Serial.print("Write from wio to zynq\n");

              Serial.print("write finish!\n");
              Serial.print("----------------------------\n");