MC6850.hh

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#ifndef MC6850_HH
#define MC6850_HH
 
#include "DynamicClock.hh"
#include "IRQHelper.hh"
#include "MidiInConnector.hh"
#include "MidiOutConnector.hh"
#include "Schedulable.hh"
#include "openmsx.hh"
#include "outer.hh"
 
namespace openmsx {
 
class Scheduler;
 
class MC6850 final : public MidiInConnector
{
public:
        MC6850(const std::string& name, MSXMotherBoard& motherBoard, unsigned clockFreq);
        void reset(EmuTime::param time);
 
        [[nodiscard]] byte readStatusReg() const;
        [[nodiscard]] byte peekStatusReg() const;
        [[nodiscard]] byte readDataReg();
        [[nodiscard]] byte peekDataReg() const;
        void writeControlReg(byte value, EmuTime::param time);
        void writeDataReg   (byte value, EmuTime::param time);
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
private:
        void setDataFormat();
 
        // MidiInConnector
        [[nodiscard]] bool ready() override;
        [[nodiscard]] bool acceptsData() override;
        void setDataBits(DataBits bits) override;
        void setStopBits(StopBits bits) override;
        void setParityBit(bool enable, Parity parity) override;
        void recvByte(byte value, EmuTime::param time) override;
 
        // Schedulable
        struct SyncRecv final : Schedulable {
                friend class MC6850;
                explicit SyncRecv(Scheduler& s) : Schedulable(s) {}
                void executeUntil(EmuTime::param time) override {
                        auto& mc6850 = OUTER(MC6850, syncRecv);
                        mc6850.execRecv(time);
                }
        } syncRecv;
        struct SyncTrans final : Schedulable {
                friend class MC6850;
                explicit SyncTrans(Scheduler& s) : Schedulable(s) {}
                void executeUntil(EmuTime::param time) override {
                        auto& mc6850 = OUTER(MC6850, syncTrans);
                        mc6850.execTrans(time);
                }
        } syncTrans;
        void execRecv (EmuTime::param time);
        void execTrans(EmuTime::param time);
 
        // External clock, divided by 1, 16 or 64.
        // Transmitted bits are synced to this clock
        DynamicClock txClock{EmuTime::zero()};
        const unsigned clockFreq;
 
        IRQHelper rxIRQ;
        IRQHelper txIRQ;
        bool rxReady;
        bool txShiftRegValid; //<! True iff txShiftReg contains a valid value
        bool pendingOVRN;     //<! Overrun detected but not yet reported.
        byte rxDataReg;       //<! Byte received from MIDI in connector.
        byte txDataReg = 0;   //<! Next to-be-sent byte.
        byte txShiftReg = 0;  //<! Byte currently being sent.
        byte controlReg;
        byte statusReg;
        byte charLen;         //<! #start- + #data- + #parity- + #stop-bits
 
        MidiOutConnector outConnector;
};
SERIALIZE_CLASS_VERSION(MC6850, 3);
 
} // namespace openmsx
 
#endif