text: /***************************************************************************
  
      Motorola 6840 (PTM)
  
      Programmable Timer Module
  
  ***************************************************************************/
  
  #pragma once
  
  #ifndef __6840PTM_H__
  #define __6840PTM_H__
  
  #include "emu.h"
  
  
  
  //**************************************************************************
  //  DEVICE CONFIGURATION MACROS
  //**************************************************************************
  
  #define MCFG_PTM6840_ADD(_tag, _interface) \
  	MCFG_DEVICE_ADD(_tag, PTM6840, 0) \
  	ptm6840_device::static_set_interface(*device, _interface);
  
  
  
  //**************************************************************************
  //  TYPE DEFINITIONS
  //**************************************************************************
  
  // ======================> ptm6840_interface
  
  struct ptm6840_interface
  {
  	double m_internal_clock;
  	double m_external_clock[3];
  
  	devcb_write8 m_out_cb[3];		// function to call when output[idx] changes
  	devcb_write_line m_irq_cb;	// function called if IRQ line changes
  };
  
  
  
  // ======================> ptm6840_device
  
  class ptm6840_device :  public device_t,
                          public ptm6840_interface
  {
  public:
      // construction/destruction
      ptm6840_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
  
  	// static configuration helpers
  	static void static_set_interface(device_t &device, const ptm6840_interface &interface);
  
  	int status(int clock) const { return m_enabled[clock]; } // get whether timer is enabled
  	int irq_state() const { return m_IRQ; }					// get IRQ state
  	UINT16 count(int counter) const { return compute_counter(counter); }	// get counter value
  	void set_ext_clock(int counter, double clock);	// set clock frequency
  	int ext_clock(int counter) const { return m_external_clock[counter]; }	// get clock frequency
  
  	DECLARE_WRITE8_MEMBER( write );
  	void write(offs_t offset, UINT8 data) { write(*memory_nonspecific_space(machine()), offset, data); }
  	DECLARE_READ8_MEMBER( read );
  	UINT8 read(offs_t offset) { return read(*memory_nonspecific_space(machine()), offset); }
  
  	void set_gate(int idx, int state);
  	DECLARE_WRITE_LINE_MEMBER( set_g1 );
  	DECLARE_WRITE_LINE_MEMBER( set_g2 );
  	DECLARE_WRITE_LINE_MEMBER( set_g3 );
  
  	void set_clock(int idx, int state);
  	DECLARE_WRITE_LINE_MEMBER( set_c1 );
  	DECLARE_WRITE_LINE_MEMBER( set_c2 );
  	DECLARE_WRITE_LINE_MEMBER( set_c3 );
  
  	void update_interrupts();
  
  protected:
      // device-level overrides
      virtual void device_start();
      virtual void device_reset();
  	virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr);
  
  private:
  	void subtract_from_counter(int counter, int count);
  	void tick(int counter, int count);
  	void timeout(int idx);
  
  	UINT16 compute_counter(int counter) const;
  	void reload_count(int idx);
  
  	enum
  	{
  		PTM_6840_CTRL1   = 0,
  		PTM_6840_CTRL2   = 1,
  		PTM_6840_STATUS  = 1,
  		PTM_6840_MSBBUF1 = 2,
  		PTM_6840_LSB1	 = 3,
  		PTM_6840_MSBBUF2 = 4,
  		PTM_6840_LSB2    = 5,
  		PTM_6840_MSBBUF3 = 6,
  		PTM_6840_LSB3    = 7,
  	};
  
  	devcb_resolved_write8 m_out_func[3];	// function to call when output[idx] changes
  	devcb_resolved_write_line m_irq_func;	// function called if IRQ line changes
  
  	UINT8 m_control_reg[3];
  	UINT8 m_output[3]; // Output states
  	UINT8 m_gate[3];   // Input gate states
  	UINT8 m_clk[3];  // Clock states
  	UINT8 m_enabled[3];
  	UINT8 m_mode[3];
  	UINT8 m_fired[3];
  	UINT8 m_t3_divisor;
  	UINT8 m_t3_scaler;
  	UINT8 m_IRQ;
  	UINT8 m_status_reg;
  	UINT8 m_status_read_since_int;
  	UINT8 m_lsb_buffer;
  	UINT8 m_msb_buffer;
  
  	// Each PTM has 3 timers
  	emu_timer *m_timer[3];
  
  	UINT16 m_latch[3];
  	UINT16 m_counter[3];
  
  	static const char *const opmode[];
  };
  
  
  // device type definition
  extern const device_type PTM6840;
  
  
  #endif /* __6840PTM_H__ */
  