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◆ main openmsx / src / serial / I8251.hh
3.0 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
// This class implements the Intel 8251 chip (UART)
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#ifndef I8251_HH
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#define I8251_HH
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#include "ClockPin.hh"
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#include "SerialDataInterface.hh"
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#include "Schedulable.hh"
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#include "serialize_meta.hh"
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#include "outer.hh"
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#include <cstdint>
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namespace openmsx {
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class I8251Interface : public SerialDataInterface
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{
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public:
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	virtual void setRxRDY(bool status, EmuTime time) = 0;
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	virtual void setDTR(bool status, EmuTime time) = 0;
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	virtual void setRTS(bool status, EmuTime time) = 0;
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	[[nodiscard]] virtual bool getDSR(EmuTime time) = 0;
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	[[nodiscard]] virtual bool getCTS(EmuTime time) = 0; // TODO use this
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	virtual void signal(EmuTime time) = 0;
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protected:
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	I8251Interface() = default;
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	~I8251Interface() = default;
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};
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class I8251 final : public SerialDataInterface
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{
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public:
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	I8251(Scheduler& scheduler, I8251Interface& interface, EmuTime time);
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	void reset(EmuTime time);
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	[[nodiscard]] uint8_t readIO(uint16_t port, EmuTime time);
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	[[nodiscard]] uint8_t peekIO(uint16_t port, EmuTime time) const;
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	void writeIO(uint16_t port, uint8_t value, EmuTime time);
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	[[nodiscard]] ClockPin& getClockPin() { return clock; }
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	[[nodiscard]] bool isRecvReady() const { return recvReady; }
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	[[nodiscard]] bool isRecvEnabled() const;
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	[[nodiscard]] bool isRecvFull() const;
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	[[nodiscard]] unsigned getBaudRateFactor() const;
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	// SerialDataInterface
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	void setDataBits(DataBits bits) override { recvDataBits = bits; }
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	void setStopBits(StopBits bits) override { recvStopBits = bits; }
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	void setParityBit(bool enable, Parity parity) override;
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	void recvByte(uint8_t value, EmuTime time) override;
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	void execRecv(EmuTime time);
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	void execTrans(EmuTime time);
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	template<typename Archive>
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	void serialize(Archive& ar, unsigned version);
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	// public for serialize
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	enum class CmdPhase : uint8_t {
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		MODE, SYNC1, SYNC2, CMD
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	};
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private:
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	void setMode(uint8_t newMode);
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	void writeCommand(uint8_t value, EmuTime time);
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	[[nodiscard]] uint8_t readStatus(EmuTime time);
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	[[nodiscard]] uint8_t readTrans(EmuTime time);
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	void writeTrans(uint8_t value, EmuTime time);
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	void send(uint8_t value, EmuTime time);
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private:
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	// Schedulable
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	struct SyncRecv final : Schedulable {
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		friend class I8251;
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		explicit SyncRecv(Scheduler& s) : Schedulable(s) {}
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		void executeUntil(EmuTime time) override {
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			auto& i8251 = OUTER(I8251, syncRecv);
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			i8251.execRecv(time);
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		}
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	} syncRecv;
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	struct SyncTrans final : Schedulable {
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		friend class I8251;
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		explicit SyncTrans(Scheduler& s) : Schedulable(s) {}
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		void executeUntil(EmuTime time) override {
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			auto& i8251 = OUTER(I8251, syncTrans);
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			i8251.execTrans(time);
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		}
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	} syncTrans;
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	I8251Interface& interface;
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	ClockPin clock;
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	unsigned charLength;
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	CmdPhase cmdPhase;
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	SerialDataInterface::DataBits  recvDataBits;
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	SerialDataInterface::StopBits  recvStopBits;
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	SerialDataInterface::Parity recvParityBit;
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	bool recvParityEnabled;
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	uint8_t recvBuf;
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	bool recvReady;
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	uint8_t sendByte;
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	uint8_t sendBuffer;
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	uint8_t status;
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	uint8_t command;
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	uint8_t mode;
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	uint8_t sync1, sync2;
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};
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SERIALIZE_CLASS_VERSION(I8251, 2);
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} // namespace openmsx
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#endif