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// license:BSD-3-Clause
// copyright-holders:Antoine Mine
/**********************************************************************

  Copyright (C) Antoine Mine' 2006

  Motorola 6846 timer emulation.

**********************************************************************/

#ifndef MC6846_H
#define MC6846_H


#define MCFG_MC6846_OUT_PORT_CB(_devcb) \
	devcb = &mc6846_device::set_out_port_callback(*device, DEVCB_##_devcb);

#define MCFG_MC6846_OUT_CP1_CB(_devcb) \
	devcb = &mc6846_device::set_out_cp1_callback(*device, DEVCB_##_devcb);

#define MCFG_MC6846_OUT_CP2_CB(_devcb) \
	devcb = &mc6846_device::set_out_cp2_callback(*device, DEVCB_##_devcb);

#define MCFG_MC6846_IN_PORT_CB(_devcb) \
	devcb = &mc6846_device::set_in_port_callback(*device, DEVCB_##_devcb);

#define MCFG_MC6846_OUT_CTO_CB(_devcb) \
	devcb = &mc6846_device::set_out_cto_callback(*device, DEVCB_##_devcb);

#define MCFG_MC6846_IRQ_CB(_devcb) \
	devcb = &mc6846_device::set_irq_callback(*device, DEVCB_##_devcb);


class mc6846_device : public device_t
{
public:
	mc6846_device(const machine_config &mconfig, std::string tag, device_t *owner, UINT32 clock);
	~mc6846_device() {}

	template<class _Object> static devcb_base &set_out_port_callback(device_t &device, _Object object) { return downcast<mc6846_device &>(device).m_out_port_cb.set_callback(object); }
	template<class _Object> static devcb_base &set_out_cp1_callback(device_t &device, _Object object) { return downcast<mc6846_device &>(device).m_out_cp1_cb.set_callback(object); }
	template<class _Object> static devcb_base &set_out_cp2_callback(device_t &device, _Object object) { return downcast<mc6846_device &>(device).m_out_cp2_cb.set_callback(object); }
	template<class _Object> static devcb_base &set_in_port_callback(device_t &device, _Object object) { return downcast<mc6846_device &>(device).m_in_port_cb.set_callback(object); }
	template<class _Object> static devcb_base &set_out_cto_callback(device_t &device, _Object object) { return downcast<mc6846_device &>(device).m_out_cto_cb.set_callback(object); }
	template<class _Object> static devcb_base &set_irq_callback(device_t &device, _Object object) { return downcast<mc6846_device &>(device).m_irq_cb.set_callback(object); }

	/* interface to CPU via address/data bus*/
	DECLARE_READ8_MEMBER(read);
	DECLARE_WRITE8_MEMBER(write);

	/* asynchronous write from outside world into interrupt-generating pins */
	void set_input_cp1(int data);
	void set_input_cp2(int data);

	/* polling from outside world */
	UINT8  get_output_port();
	UINT8  get_output_cto();
	UINT8  get_output_cp2();

	/* partial access to internal state */
	UINT16 get_preset(); /* timer interval - 1 in us */

protected:
	// device-level overrides
	virtual void device_start() override;
	virtual void device_reset() override;

private:
	// internal state

	/* registers */
	UINT8    m_csr;      /* 0,4: combination status register */
	UINT8    m_pcr;      /* 1:   peripheral control register */
	UINT8    m_ddr;      /* 2:   data direction register */
	UINT8    m_pdr;      /* 3:   peripheral data register (last cpu write) */
	UINT8    m_tcr;      /* 5:   timer control register */

	/* lines */
	UINT8 m_cp1;         /* 1-bit input */
	UINT8 m_cp2;         /* 1-bit input/output: last external write */
	UINT8 m_cp2_cpu;     /* last cpu write */
	UINT8 m_cto;         /* 1-bit timer output (unmasked) */

	/* internal state */
	UINT8  m_time_MSB; /* MSB buffer register */
	UINT8  m_csr0_to_be_cleared;
	UINT8  m_csr1_to_be_cleared;
	UINT8  m_csr2_to_be_cleared;
	UINT16 m_latch;   /* timer latch */
	UINT16 m_preset;  /* preset value */
	UINT8  m_timer_started;

	/* timers */
	emu_timer *m_interval; /* interval programmable timer */
	emu_timer *m_one_shot; /* 1-us x factor one-shot timer */

	/* CPU write to the outside through chip */
	devcb_write8 m_out_port_cb;  /* 8-bit output */
	devcb_write8 m_out_cp1_cb;   /* 1-bit output */
	devcb_write8 m_out_cp2_cb;   /* 1-bit output */

	/* CPU read from the outside through chip */
	devcb_read8 m_in_port_cb; /* 8-bit input */

	/* asynchronous timer output to outside world */
	devcb_write8 m_out_cto_cb; /* 1-bit output */

	/* timer interrupt */
	devcb_write_line m_irq_cb;

	int m_old_cif;
	int m_old_cto;

	inline UINT16 counter();
	inline void update_irq();
	inline void update_cto();
	inline void timer_launch();

	TIMER_CALLBACK_MEMBER(timer_expire);
	TIMER_CALLBACK_MEMBER(timer_one_shot);
};

extern const device_type MC6846;

#endif