// $Id: I8251.hh 5993 2007-01-12 22:12:12Z m9710797 $

// This class implements the Intel 8251 chip (UART)

#ifndef I8251_HH
#define I8251_HH

#include "ClockPin.hh"
#include "SerialDataInterface.hh"
#include "Schedulable.hh"
#include "openmsx.hh"

namespace openmsx {

class EmuTime;

class I8251Interface : public SerialDataInterface
{
public:
	virtual ~I8251Interface() {}
	virtual void setRxRDY(bool status, const EmuTime& time) = 0;
	virtual void setDTR(bool status, const EmuTime& time) = 0;
	virtual void setRTS(bool status, const EmuTime& time) = 0;
	virtual bool getDSR(const EmuTime& time) = 0;
	virtual bool getCTS(const EmuTime& time) = 0; // TODO use this
	virtual void signal(const EmuTime& time) = 0;
};

class I8251 : public SerialDataInterface, private Schedulable
{
public:
	I8251(Scheduler& scheduler, I8251Interface* interf, const EmuTime& time);

	void reset(const EmuTime& time);
	byte readIO(word port, const EmuTime& time);
	byte peekIO(word port, const EmuTime& time) const;
	void writeIO(word port, byte value, const EmuTime& time);
	ClockPin& getClockPin();
	bool isRecvReady();
	bool isRecvEnabled();

	// SerialDataInterface
	virtual void setDataBits(DataBits bits);
	virtual void setStopBits(StopBits bits);
	virtual void setParityBit(bool enable, ParityBit parity);
	virtual void recvByte(byte value, const EmuTime& time);

	// Schedulable
	virtual void executeUntil(const EmuTime& time, int userData);
	virtual const std::string& schedName() const;

private:
	void setMode(byte mode);
	void writeCommand(byte value, const EmuTime& time);
	byte readStatus(const EmuTime& time);
	byte readTrans(const EmuTime& time);
	void writeTrans(byte value, const EmuTime& time);
	void send(byte value, const EmuTime& time);

	I8251Interface* interf;
	enum CmdFaze {
		FAZE_MODE, FAZE_SYNC1, FAZE_SYNC2, FAZE_CMD
	} cmdFaze;
	byte status;
	byte command;
	byte mode;
	byte sync1, sync2;
	ClockPin clock;
	unsigned charLength;

	SerialDataInterface::DataBits  recvDataBits;
	SerialDataInterface::StopBits  recvStopBits;
	bool                           recvParityEnabled;
	SerialDataInterface::ParityBit recvParityBit;
	byte                           recvBuf;
	bool recvReady;

	byte sendByte;
	byte sendBuffer;
	bool sendBuffered;
};

} // namespace openmsx

#endif