// license:BSD-3-Clause
// copyright-holders:Antoine Mine
/**********************************************************************
Copyright (C) Antoine Mine' 2006
Motorola 6854 emulation (network interface).
**********************************************************************/
#ifndef MC6854_H
#define MC6854_H
#define MAX_FRAME_LENGTH 65536
/* arbitrary value, you may need to enlarge it if you get truncated frames */
#define MC6854_FIFO_SIZE 3
/* hardcoded size of the 6854 FIFO (this is a hardware limit) */
typedef device_delegate<void (UINT8 *data, int length)> mc6854_out_frame_delegate;
#define MC6854_OUT_FRAME_CB(name) void name(UINT8 * data, int length)
#define MCFG_MC6854_OUT_IRQ_CB(_devcb) \
devcb = &mc6854_device::set_out_irq_callback(*device, DEVCB_##_devcb);
#define MCFG_MC6854_OUT_TXD_CB(_devcb) \
devcb = &mc6854_device::set_out_txd_callback(*device, DEVCB_##_devcb);
#define MCFG_MC6854_OUT_FRAME_CB(_class, _method) \
mc6854_device::set_out_frame_callback(*device, mc6854_out_frame_delegate(&_class::_method, #_class "::" #_method, downcast<_class *>(owner)));
#define MCFG_MC6854_OUT_RTS_CB(_devcb) \
devcb = &mc6854_device::set_out_rts_callback(*device, DEVCB_##_devcb);
#define MCFG_MC6854_OUT_DTR_CB(_devcb) \
devcb = &mc6854_device::set_out_dtr_callback(*device, DEVCB_##_devcb);
class mc6854_device : public device_t
{
public:
mc6854_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
~mc6854_device() {}
template<class _Object> static devcb_base &set_out_irq_callback(device_t &device, _Object object) { return downcast<mc6854_device &>(device).m_out_irq_cb.set_callback(object); }
template<class _Object> static devcb_base &set_out_txd_callback(device_t &device, _Object object) { return downcast<mc6854_device &>(device).m_out_txd_cb.set_callback(object); }
static void set_out_frame_callback(device_t &device, mc6854_out_frame_delegate callback) { downcast<mc6854_device &>(device).m_out_frame_cb = callback; }
template<class _Object> static devcb_base &set_out_rts_callback(device_t &device, _Object object) { return downcast<mc6854_device &>(device).m_out_rts_cb.set_callback(object); }
template<class _Object> static devcb_base &set_out_dtr_callback(device_t &device, _Object object) { return downcast<mc6854_device &>(device).m_out_dtr_cb.set_callback(object); }
/* interface to CPU via address/data bus*/
DECLARE_READ8_MEMBER( read );
DECLARE_WRITE8_MEMBER( write );
/* low-level, bit-based interface */
DECLARE_WRITE_LINE_MEMBER( set_rx );
/* high-level, frame-based interface */
int send_frame( UINT8* data, int length ); /* ret -1 if busy */
/* control lines */
DECLARE_WRITE_LINE_MEMBER( set_cts ); /* 1 = clear-to-send, 0 = busy */
DECLARE_WRITE_LINE_MEMBER( set_dcd ); /* 1 = carrier, 0 = no carrier */
/* clock */
DECLARE_WRITE_LINE_MEMBER( rxc_w );
DECLARE_WRITE_LINE_MEMBER( txc_w );
protected:
// device-level overrides
virtual void device_start() override;
virtual void device_reset() override;
private:
// internal state
devcb_write_line m_out_irq_cb; /* interrupt request */
/* low-level, bit-based interface */
devcb_write_line m_out_txd_cb; /* transmit bit */
/* high-level, frame-based interface */
mc6854_out_frame_delegate m_out_frame_cb;
/* control lines */
devcb_write_line m_out_rts_cb; /* 1 = transmitting, 0 = idle */
devcb_write_line m_out_dtr_cb; /* 1 = data transmit ready, 0 = busy */
/* registers */
UINT8 m_cr1, m_cr2, m_cr3, m_cr4; /* control registers */
UINT8 m_sr1, m_sr2; /* status registers */
UINT8 m_cts, m_dcd;
/* transmit state */
UINT8 m_tstate;
UINT16 m_tfifo[MC6854_FIFO_SIZE]; /* X x 8-bit FIFO + full & last marker bits */
UINT8 m_tones; /* counter for zero-insertion */
emu_timer *m_ttimer; /* when to ask for more data */
/* receive state */
UINT8 m_rstate;
UINT32 m_rreg; /* shift register */
UINT8 m_rones; /* count '1 bits */
UINT8 m_rsize; /* bits in the shift register */
UINT16 m_rfifo[MC6854_FIFO_SIZE]; /* X x 8-bit FIFO + full & addr marker bits */
/* frame-based interface*/
UINT8 m_frame[MAX_FRAME_LENGTH];
UINT32 m_flen, m_fpos;
/* meaning of tstate / rtate:
0 = idle / waiting for frame flag
1 = flag sync
2 = 8-bit address field(s)
3-4 = 8-bit control field(s)
5 = 8-bit logical control field(s)
6 = variable-length data field(s)
*/
void send_bits( UINT32 data, int len, int zi );
void tfifo_push( UINT8 data );
void tfifo_terminate( );
TIMER_CALLBACK_MEMBER(tfifo_cb);
void tfifo_clear( );
void rfifo_push( UINT8 d );
void rfifo_terminate( );
UINT8 rfifo_pop( );
void rfifo_clear( );
void update_sr2( );
void update_sr1( );
};
extern const device_type MC6854;
/* we provide two interfaces:
- a bit-based interface: out_tx, set_rx
- a frame-based interface: out_frame, send_frame
The bit-based interface is low-level and slow.
Use it to simulate the actual bits sent into the wires, e.g., to connect
the emulator to another bit-based emulated network device, or an actual
device.
The frame-based interface is higher-level and faster.
It passes bytes directly from one end to the other without bothering with
the actual bit-encoding, synchronization, and CRC.
Once completed, a frame is sent through out_frame. Aborted frames are not
transmitted at all. No start flag, stop flag, or crc bits are trasmitted.
send_frame makes a frame available to the CPU through the 6854 (it may
fail and return -1 if the 6854 is not ready to accept the frame; even
if the frame is accepted and 0 is returned, the CPU may abort it). Ony
full frames are accepted.
*/
#endif