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Diffstat (limited to 'src/emu/machine/mc6854.h')
-rw-r--r-- | src/emu/machine/mc6854.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/src/emu/machine/mc6854.h b/src/emu/machine/mc6854.h new file mode 100644 index 00000000000..e2c5ee3909c --- /dev/null +++ b/src/emu/machine/mc6854.h @@ -0,0 +1,100 @@ +/********************************************************************** + + 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 |