Reading Command: How to receive returning data from the shield

[sonhan]

The library is lacking the functions with returning values such as check status, check volume, check number of files. One possible is to enable Arduino RX interrupt, isn't it?

[JiapengLi]

Hardware Serial:
Use Serial.available(); to check if there is data in RX buffer, use Serial.read() to read serial data.
Check the user manual to see the format of the return value.

Software Serial:
Add extern SoftwareSerial COM_SOFT; to Arduino example.
Use COM_SOFT.available(); to check if there is data in RX buffer, use COM_SOFT.read() to read serial data.

[sonhan]

I tried with following code to check the playing status (Check Work State) but the output always is ~�Ã~status test

unsigned char cmd_buf[10];
unsigned char i;

void ArduinoMP3Shield_SendCMD(unsigned char *cmd_buf, unsigned len)
{
    unsigned i;
    for(i=0; i<len; i++){
        Serial.write(cmd_buf[i]);
    }
}

void setup(void)
{
    /** wait until arduino mp3 shield get ready */
    delay(1000);

    Serial.begin(9600);

    /** set volume */
    cmd_buf[0] = 0x7E;          // START
    cmd_buf[1] = 0x03;          // Length
    cmd_buf[2] = 0xA7;          // Command
    cmd_buf[3] = 0x0F;          // new volume
    cmd_buf[4] = 0x7E;          // END
    ArduinoMP3Shield_SendCMD(cmd_buf, 5);

    /** set play mode repeat all */
    cmd_buf[0] = 0x7E;          // START
    cmd_buf[1] = 0x03;          // Length
    cmd_buf[2] = 0xA9;          // Command SET MODE
    cmd_buf[3] = 0x00;          // set mode
    cmd_buf[4] = 0x7E;          // END
    ArduinoMP3Shield_SendCMD(cmd_buf, 5);

    /** select SD card first music and play */
    cmd_buf[0] = 0x7E;          // START
    cmd_buf[1] = 0x04;          // Length
    cmd_buf[2] = 0xA0;          // Command
    cmd_buf[3] = 0x00;          // file number high byte
    cmd_buf[4] = 0x03;          // file number low byte
    cmd_buf[5] = 0x7E;          // END
    ArduinoMP3Shield_SendCMD(cmd_buf, 6);
}

void loop(void)
{
  delay(2000);
  Serial.println("status test");  
  cmd_buf[0] = 0x7E;
  cmd_buf[1] = 0x02;
  cmd_buf[2] = 0xC3;
  cmd_buf[3] = 0x7E;
  ArduinoMP3Shield_SendCMD(cmd_buf, 4);
  if(Serial.available()) {
      byte c = Serial.read();
      if (c == 0x01) Serial.println("playing");
      else if (c == 0x02) Serial.println("stop");
      else if (c == 0x02) Serial.println("pause");
      else Serial.println("nothing");
  }
}

[sonhan]

Sorry here is the code and output is always (no matter it is playing or not or pause)

status test
�Ânothing
status test
�Âstop
status test
�Ânothing
status test
�Âstop
status test
�Ânothing
status test
�Âstop

unsigned char cmd_buf[10];
unsigned char i;

void ArduinoMP3Shield_SendCMD(unsigned char *cmd_buf, unsigned len)
{
    unsigned i;
    for(i=0; i<len; i++){
        Serial.write(cmd_buf[i]);
    }
}

void setup(void)
{
    /** wait until arduino mp3 shield get ready */
    delay(1000);

    Serial.begin(9600);

    /** set volume */
    cmd_buf[0] = 0x7E;          // START
    cmd_buf[1] = 0x03;          // Length
    cmd_buf[2] = 0xA7;          // Command
    cmd_buf[3] = 0x0F;          // new volume
    cmd_buf[4] = 0x7E;          // END
    ArduinoMP3Shield_SendCMD(cmd_buf, 5);

    /** set play mode repeat all */
    cmd_buf[0] = 0x7E;          // START
    cmd_buf[1] = 0x03;          // Length
    cmd_buf[2] = 0xA9;          // Command SET MODE
    cmd_buf[3] = 0x00;          // set mode
    cmd_buf[4] = 0x7E;          // END
    ArduinoMP3Shield_SendCMD(cmd_buf, 5);

    /** select SD card first music and play */
    cmd_buf[0] = 0x7E;          // START
    cmd_buf[1] = 0x04;          // Length
    cmd_buf[2] = 0xA0;          // Command
    cmd_buf[3] = 0x00;          // file number high byte
    cmd_buf[4] = 0x03;          // file number low byte
    cmd_buf[5] = 0x7E;          // END
    ArduinoMP3Shield_SendCMD(cmd_buf, 6);
}

void loop(void)
{
  delay(1000);
  Serial.println("status test");  
  cmd_buf[0] = 0x7E;
  cmd_buf[1] = 0x02;
  cmd_buf[2] = 0xC2;
  cmd_buf[3] = 0x7E;
  ArduinoMP3Shield_SendCMD(cmd_buf, 4);
  if(Serial.available()) {
      byte c = Serial.read();
      if (c == 0x01) Serial.println("playing");
      else if (c == 0x02) Serial.println("stop");
      else if (c == 0x03) Serial.println("pause");
      else Serial.println("nothing");
  }
}

[sonhan]

And if I read 02 bytes (command, value) the output is always nothing

void loop(void)
{
  delay(1000);
  Serial.println("status test");  
  cmd_buf[0] = 0x7E;
  cmd_buf[1] = 0x02;
  cmd_buf[2] = 0xC2;
  cmd_buf[3] = 0x7E;
  ArduinoMP3Shield_SendCMD(cmd_buf, 4);
  if(Serial.available()) {
      byte command = Serial.read();  
      byte value = Serial.read();
      if (value == 0x01) Serial.println("playing");
      else if (value == 0x02) Serial.println("stop");
      else if (value == 0x03) Serial.println("pause");
      else Serial.println("nothing");
  }
}