/********************************************************************** Copyright (C) Antoine Mine' 2006 Motorola 6854 emulation (network interface). **********************************************************************/ #ifndef MC6854_H #define MC6854_H class mc6854_device : public device_t { public: mc6854_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock); ~mc6854_device() { global_free(m_token); } // access to legacy token void *token() const { assert(m_token != NULL); return m_token; } protected: // device-level overrides virtual void device_config_complete(); virtual void device_start(); virtual void device_reset(); private: // internal state void *m_token; }; 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. */ /* ---------- configuration ------------ */ struct mc6854_interface { devcb_write_line out_irq_func; /* interrupt request */ /* low-level, bit-based interface */ devcb_read_line in_rxd_func; /* receive bit */ devcb_write_line out_txd_func; /* transmit bit */ /* high-level, frame-based interface */ void ( * out_frame ) ( device_t *device, UINT8* data, int length ); /* control lines */ devcb_write_line out_rts_func; /* 1 = transmitting, 0 = idle */ devcb_write_line out_dtr_func; /* 1 = data transmit ready, 0 = busy */ }; #define MCFG_MC6854_ADD(_tag, _intrf) \ MCFG_DEVICE_ADD(_tag, MC6854, 0) \ MCFG_DEVICE_CONFIG(_intrf) #define MCFG_MC6854_REMOVE(_tag) \ MCFG_DEVICE_REMOVE(_tag) /* ---------- functions ------------ */ /* interface to CPU via address/data bus*/ extern DECLARE_READ8_DEVICE_HANDLER ( mc6854_r ); extern DECLARE_WRITE8_DEVICE_HANDLER ( mc6854_w ); /* low-level, bit-based interface */ WRITE_LINE_DEVICE_HANDLER( mc6854_set_rx ); /* high-level, frame-based interface */ extern int mc6854_send_frame( device_t *device, UINT8* data, int length ); /* ret -1 if busy */ /* control lines */ WRITE_LINE_DEVICE_HANDLER( mc6854_set_cts ); /* 1 = clear-to-send, 0 = busy */ WRITE_LINE_DEVICE_HANDLER( mc6854_set_dcd ); /* 1 = carrier, 0 = no carrier */ /* clock */ WRITE_LINE_DEVICE_HANDLER( mc6854_rxc_w ); WRITE_LINE_DEVICE_HANDLER( mc6854_txc_w ); #endif