mc6850.h

//
//
//	mc6850.h
//
//	(C) R.P.Bellis 1994
//

#pragma once

#include "device.h"
#include "wiring.h"

class mc6850_impl {

public:
	virtual bool		poll_read() = 0;
	virtual bool		poll_write() { return true; };

public:
	virtual Byte		read() = 0;
	virtual void		write(Byte) = 0;

public:
						mc6850_impl() = default;
	virtual				~mc6850_impl() = default;
};

class mc6850 : virtual public ActiveMappedDevice {

protected:
	enum sr_flags : Byte {
		RDRF	= 0x01,
		TDRE	= 0x02,
		DCDB	= 0x04,
		CTSB	= 0x08,
		FE		= 0x10,
		OVRN	= 0x20,
		PE		= 0x40,
		IRQB	= 0x80
	};

// Internal registers
protected:

	Byte				td, rd, cr, sr;

// Access to real IO device
	mc6850_impl&		impl;
	uint16_t			interval;	// how often to poll
	uint16_t			cycles;		// cycles since last poll

// Initialisation functions

protected:
	virtual void		tick(uint8_t);
	virtual void		reset();

// Read and write functions
public:

	virtual Byte		read(Word offset);
	virtual void		write(Word offset, Byte val);

// Other exposed interfaces
public:
	OutputPinReg		IRQ;

// Public constructor and destructor

						mc6850(mc6850_impl& impl, uint16_t interval = 1000);
	virtual				~mc6850();

};