[arduino Mega2560]I2C 練習

看到文章說,最大只能傳送32 bytes,有看到說更改底層的define就可使用超過 32 bytes
而這邊是為了要讀取64 bytes因為是練習,所以就把他拆而兩次讀,重點是要了解其I2C R/W程式寫法:

參考:
https://www.arduino.cc/en/Reference/Wire




#include <Wire.h>

bool send_step1_ok_flag;
bool send_step2_ok_flag;

byte buffer[64];
byte buffer_count;
byte slave_address=0x55;

void setup()
{
  Serial.begin(9600);

  while(!Serial) ;

  Serial.println("Serail port working...");

  send_step1_ok_flag=false;
  send_step2_ok_flag=false;

  Wire.begin();
}

void I2C_cmd_send(byte start_address)
{
  byte length=32;
  Wire.beginTransmission(slave_address);
  Wire.write(start_address);
  Wire.endTransmission();
  Wire.requestFrom(slave_address,length);
}

void loop()
{
  if((!send_step1_ok_flag)&&(!send_step2_ok_flag))
  {
    Serial.println("Master Send I2C cmd");
    send_step1_ok_flag=true;
    I2C_cmd_send(0);
    buffer_count=0;
  }
  else if((send_step1_ok_flag)&&(!send_step2_ok_flag))
  {
    if(buffer_count==32)
    {
      send_step2_ok_flag=true;
      I2C_cmd_send(32);
    }
  }
  else
  {
        Serial.println("Master Read finish");
      for(byte i=0;i<64;i++)
      {
        Serial.print(buffer[i],HEX);
        Serial.print(" ");
      }
      Serial.println();
   
      send_step1_ok_flag=false;
      send_step2_ok_flag=false;
       delay(1000);
     
  }

  while(Wire.available())
  {
    buffer[buffer_count]=Wire.read();
    buffer_count=buffer_count+1;
  }

}