I8251.hh

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// This class implements the Intel 8251 chip (UART)
 
#ifndef I8251_HH
#define I8251_HH
 
#include "ClockPin.hh"
#include "SerialDataInterface.hh"
#include "Schedulable.hh"
#include "serialize_meta.hh"
#include "openmsx.hh"
#include "outer.hh"
 
namespace openmsx {
 
class I8251Interface : public SerialDataInterface
{
public:
        virtual void setRxRDY(bool status, EmuTime::param time) = 0;
        virtual void setDTR(bool status, EmuTime::param time) = 0;
        virtual void setRTS(bool status, EmuTime::param time) = 0;
 
        [[nodiscard]] virtual bool getDSR(EmuTime::param time) = 0;
        [[nodiscard]] virtual bool getCTS(EmuTime::param time) = 0; // TODO use this
        virtual void signal(EmuTime::param time) = 0;
 
protected:
        I8251Interface() = default;
        ~I8251Interface() = default;
};
 
class I8251 final : public SerialDataInterface
{
public:
        I8251(Scheduler& scheduler, I8251Interface& interface, EmuTime::param time);
 
        void reset(EmuTime::param time);
        [[nodiscard]] byte readIO(word port, EmuTime::param time);
        [[nodiscard]] byte peekIO(word port, EmuTime::param time) const;
        void writeIO(word port, byte value, EmuTime::param time);
        [[nodiscard]] ClockPin& getClockPin() { return clock; }
        [[nodiscard]] bool isRecvReady() const { return recvReady; }
        [[nodiscard]] bool isRecvEnabled() const;
 
        // SerialDataInterface
        void setDataBits(DataBits bits) override { recvDataBits = bits; }
        void setStopBits(StopBits bits) override { recvStopBits = bits; }
        void setParityBit(bool enable, Parity parity) override;
        void recvByte(byte value, EmuTime::param time) override;
 
        void execRecv(EmuTime::param time);
        void execTrans(EmuTime::param time);
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
        // public for serialize
        enum class CmdPhase {
                MODE, SYNC1, SYNC2, CMD
        };
 
private:
        void setMode(byte newMode);
        void writeCommand(byte value, EmuTime::param time);
        [[nodiscard]] byte readStatus(EmuTime::param time);
        [[nodiscard]] byte readTrans(EmuTime::param time);
        void writeTrans(byte value, EmuTime::param time);
        void send(byte value, EmuTime::param time);
 
private:
        // Schedulable
        struct SyncRecv final : Schedulable {
                friend class I8251;
                explicit SyncRecv(Scheduler& s) : Schedulable(s) {}
                void executeUntil(EmuTime::param time) override {
                        auto& i8251 = OUTER(I8251, syncRecv);
                        i8251.execRecv(time);
                }
        } syncRecv;
        struct SyncTrans final : Schedulable {
                friend class I8251;
                explicit SyncTrans(Scheduler& s) : Schedulable(s) {}
                void executeUntil(EmuTime::param time) override {
                        auto& i8251 = OUTER(I8251, syncTrans);
                        i8251.execTrans(time);
                }
        } syncTrans;
 
        I8251Interface& interface;
        ClockPin clock;
        unsigned charLength;
 
        CmdPhase cmdPhase;
        SerialDataInterface::DataBits  recvDataBits;
        SerialDataInterface::StopBits  recvStopBits;
        SerialDataInterface::Parity recvParityBit;
        bool recvParityEnabled;
        byte recvBuf;
        bool recvReady;
 
        byte sendByte;
        byte sendBuffer;
 
        byte status;
        byte command;
        byte mode;
        byte sync1, sync2;
};
SERIALIZE_CLASS_VERSION(I8251, 2);
 
} // namespace openmsx
 
#endif