mame/src/emu/machine/tms9902.h

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

    TMS9902 Asynchronous Communication Controller
    See tms9902.c for documentation

    Michael Zapf

    February 2012: Rewritten as class

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

#ifndef __TMS9902_H__
#define __TMS9902_H__

#include "emu.h"

// Serial control protocol values
#define TYPE_TMS9902 0x01

// Configuration (output only)
#define CONFIG   0x80
#define RATERECV 0x70
#define RATEXMIT 0x60
#define DATABITS 0x50
#define STOPBITS 0x40
#define PARITY   0x30

// Exceptional states (BRK: both directions; FRMERR/PARERR: input only)
#define EXCEPT 0x40
#define BRK    0x02
#define FRMERR 0x04
#define PARERR 0x06

// Line states (RTS, DTR: output; CTS, DSR, RI, DCD: input)
#define LINES 0x00
#define RTS 0x20
#define CTS 0x10
#define DSR 0x08
#define DCD 0x04
#define DTR 0x02
#define RI  0x01

extern const device_type TMS9902;

struct tms9902_interface 
{
	devcb_write_line	int_callback;
	devcb_write_line	rcv_callback;
	devcb_write8		xmit_callback;
	devcb_write8		ctrl_callback;
};

class tms9902_device : public device_t
{
public:
	tms9902_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
	void	set_clock(bool state);

	void	rcv_cts(line_state state);
	void	rcv_dsr(line_state state);
	void	rcv_data(UINT8 data);
	void	rcv_break(bool value);
	void	rcv_framing_error();
	void	rcv_parity_error();

	double	get_baudpoll();

	int		get_config_value();

	DECLARE_READ8_MEMBER( cruread );
	DECLARE_WRITE8_MEMBER( cruwrite );

protected:
	void	device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr);
	void	device_start();
	void	device_reset();
	void	device_stop();

private:
	void	field_interrupts();
	void	reload_interval_timer();
	void	send_break(bool state);
	void	set_receive_data_rate();
	void	set_transmit_data_rate();
	void	set_stop_bits();
	void	set_data_bits();
	void	set_parity();
	void	transmit_line_state();
	void	set_rts(line_state state);
	void	initiate_transmit();
	void	reset_uart();

	devcb_resolved_write_line		int_callback;
	devcb_resolved_write_line		rcv_callback;
	devcb_resolved_write8			xmit_callback;
	devcb_resolved_write8			ctrl_callback;		// needs to be used with get_config_value

	// tms9902 clock rate (PHI* pin, normally connected to TMS9900 Phi3*)
	// Official range is 2MHz-3.3MHz.  Some tms9902s were sold as "MP9214", and
	// were tested for speeds up to 4MHz, provided the clk4m control bit is set.
	// (warning: 3MHz on a tms9900 is equivalent to 12MHz on a tms9995 or tms99000)
	double	m_clock_rate;

	/* Modes */
	bool	m_LDCTRL;		// Load control register
	bool	m_LDIR;			// Load interval register
	bool	m_LRDR;			// Load receive data register
	bool	m_LXDR;			// Load transmit data register
	bool	m_TSTMD;			// Test mode

	/* output pin */
	bool	m_RTSON;			// RTS-on request

	/* transmitter registers */
	bool	m_BRKON;			// BRK-on request
	bool	m_BRKout;		// indicates the current BRK state

	UINT8	m_XBR;			// transmit buffer register
	UINT8	m_XSR;			// transmit shift register

	/* receiver registers */
	UINT8	m_RBR;			// Receive buffer register

	/* Interrupt enable flags */
	bool	m_DSCENB;		// Data set change interrupt enable
	bool	m_RIENB;			// Receiver interrupt enable
	bool	m_XBIENB;		// Tansmit buffer interrupt enable
	bool	m_TIMENB;		// Timer interrupt enable

	/*
        Rate registers. The receive bit rate calculates as
        bitrate = clock1 / (2 * (8 ^ RDV8) * RDR)
        (similarly for transmit)

        where clock1 = clock_rate / (CLK4M? 4:3)
    */
	UINT16	m_RDR;			// Receive data rate
	bool	m_RDV8;			// Receive data rate divider
	UINT16	m_XDR;			// Transmit data rate
	bool	m_XDV8;			// Transmit data rate divider

	/* Status flags */
	bool	m_INT;			// mirrors /INT output line, inverted
	bool	m_DSCH;			// Data set status change

	bool	m_CTSin;			// Inverted /CTS input (i.e. CTS)
	bool	m_DSRin;			// Inverted /DSR input (i.e. DSR)
	bool	m_RTSout;		// Current inverted /RTS line state (i.e. RTS)

	bool	m_TIMELP;		// Timer elapsed
	bool	m_TIMERR;		// Timer error

	bool	m_XSRE;			// Transmit shift register empty
	bool	m_XBRE;			// Transmit buffer register empty
	bool	m_RBRL;			// Receive buffer register loaded

	bool	m_RIN;			// State of the RIN pin
	bool	m_RSBD;			// Receive start bit detect
	bool	m_RFBD;			// Receive full bit detect
	bool	m_RFER;			// Receive framing error
	bool	m_ROVER;			// Receiver overflow
	bool	m_RPER;			// Receive parity error

	UINT8	m_RCL;			// Character length
	bool	m_ODDP;
	bool	m_PENB;
	UINT8	m_STOPB;
	bool	m_CLK4M;		// /PHI input divide select

	UINT8	m_TMR;		/* interval timer */

	/* clock registers */
	emu_timer *m_dectimer;			/* MESS timer, used to emulate the decrementer register */
	emu_timer *m_recvtimer;
	emu_timer *m_sendtimer;

	// This value is the ratio of data input versus the poll rate. The
	// data source should deliver data bytes at every 1/baudpoll call.
	// This is to ensure that data is delivered at a rate that is expected
	// from the emulated program.
	double	m_baudpoll;

	// Caches the last configuration setting (used with the ctrl_callback)
	int		m_last_config_value;
};

/***************************************************************************
    DEVICE CONFIGURATION MACROS
***************************************************************************/

#define MCFG_TMS9902_ADD(_tag, _intrf, _clock) \
	MCFG_DEVICE_ADD(_tag, TMS9902, _clock) \
	MCFG_DEVICE_CONFIG(_intrf)

#endif /* __TMS9902_H__ */