DFPlayerMini.h

#pragma once

#include <Arduino.h>
#include <stdint.h>

struct DFPResponse; // defined below

class DFPlayerMini {
public:
    static const uint8_t BufferLength = 10;
    static const uint8_t MinimumTimeMs = 20;
    static const uint8_t ResponseTimeoutMs = 20;

    // Structure of the command packet
    static const uint8_t PacketOffsetCmd = 3;
    static const uint8_t PacketOffsetArg = 5;
    static const uint8_t PacketOffsetCkSum = 7;

public:

    enum Cmd {                  
        Undefined       = 0x00, 
        Next            = 0x01, 
        Prev            = 0x02, 
        PlayPhysical    = 0x03, 
        SetVolume       = 0x06, 
        SetEqalizer     = 0x07, 
        SetDevice       = 0x09, 
        Sleep           = 0x0A, 
        Reset           = 0x0C, 
        Play            = 0x0D, 
        Pause           = 0x0E, 
        PlayTf          = 0x12, 
        Stop            = 0x16, 
        SingleLoop      = 0x19, 
        GetStatus       = 0x42, 
        GetVolume       = 0x43, 
        GetUSum         = 0x47, 
        GetTfSum        = 0x48, 
        GetFlashSum     = 0x49, 
        GetUCurrent     = 0x4B, 
        GetTfCurrent    = 0x4C, 
        GetFlashCurrent = 0x4D  
    };

    DFPlayerMini(Stream& serial, const uint8_t busyPin=0);

    void begin(bool bootWait=true);

    void sendCmd(Cmd cmd, uint16_t arg=0);

    DFPResponse query(Cmd cmd, uint8_t tries=3);

    bool busy();

    bool check();

private:
    DFPResponse _query(Cmd cmd);

    void resetSendBuf();
    void copyBigend(uint8_t *thebuf, uint16_t data);
    void fillChecksum();
    uint16_t calculateChecksum(uint8_t *thebuf);
    void serialCmd();

private:
    Stream& _serial;
    const uint8_t _busyPin;
    uint8_t _sendBuf[BufferLength];
    uint32_t _lastCmdSent;

};

struct DFPResponse {
    enum Status {
        Incomplete=0,     
        Ok=1,             
        Timeout=2,        
        SerialError=3,    
        Invalid=4         
    };

    DFPResponse() : status(Incomplete), messageType(0), arg(0) {;}

    // Data members.
    Status status;
    uint8_t messageType;
    uint16_t arg;
};