// license:BSD-3-Clause // copyright-holders:Antoine Mine /********************************************************************** Copyright (C) Antoine Mine' 2006 Motorola 6854 emulation (network interface). **********************************************************************/ #ifndef MAME_MACHINE_MC6854_H #define MAME_MACHINE_MC6854_H #pragma once class mc6854_device : public device_t { public: static constexpr unsigned MAX_FRAME_LENGTH = 65536; // arbitrary value, you may need to enlarge it if you get truncated frames typedef device_delegate out_frame_delegate; mc6854_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock = 0); auto out_irq_cb() { return m_out_irq_cb.bind(); } auto out_txd_cb() { return m_out_txd_cb.bind(); } auto out_rts_cb() { return m_out_rts_cb.bind(); } auto out_dtr_cb() { return m_out_dtr_cb.bind(); } template void set_out_frame_callback(Object &&cb) { m_out_frame_cb = std::forward(cb); } void set_out_frame_callback(out_frame_delegate callback) { m_out_frame_cb = callback; } template void set_out_frame_callback(const char *devname, void (FunctionClass::*callback)(uint8_t *, int), const char *name) { set_out_frame_callback(out_frame_delegate(callback, name, devname, static_cast(nullptr))); } template void set_out_frame_callback(void (FunctionClass::*callback)(uint8_t *, int), const char *name) { set_out_frame_callback(out_frame_delegate(callback, name, nullptr, static_cast(nullptr))); } /* interface to CPU via address/data bus*/ uint8_t read(offs_t offset); void write(offs_t offset, uint8_t data); /* low-level, bit-based interface */ DECLARE_WRITE_LINE_MEMBER( set_rx ); /* high-level, frame-based interface */ int send_frame( uint8_t* 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: static constexpr unsigned FIFO_SIZE = 3; // hardcoded size of the 6854 FIFO (this is a hardware limit) // 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 */ 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_t m_cr1, m_cr2, m_cr3, m_cr4; /* control registers */ uint8_t m_sr1, m_sr2; /* status registers */ uint8_t m_cts, m_dcd; /* transmit state */ uint8_t m_tstate; uint16_t m_tfifo[FIFO_SIZE]; /* X x 8-bit FIFO + full & last marker bits */ uint8_t m_tones; /* counter for zero-insertion */ emu_timer *m_ttimer; /* when to ask for more data */ /* receive state */ uint8_t m_rstate; uint32_t m_rreg; /* shift register */ uint8_t m_rones; /* count '1 bits */ uint8_t m_rsize; /* bits in the shift register */ uint16_t m_rfifo[FIFO_SIZE]; /* X x 8-bit FIFO + full & addr marker bits */ /* frame-based interface*/ uint8_t m_frame[MAX_FRAME_LENGTH]; uint32_t 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_t data, int len, int zi ); void tfifo_push( uint8_t data ); void tfifo_terminate( ); TIMER_CALLBACK_MEMBER(tfifo_cb); void tfifo_clear( ); void rfifo_push( uint8_t d ); void rfifo_terminate( ); uint8_t rfifo_pop( ); void rfifo_clear( ); void update_sr2( ); void update_sr1( ); }; DECLARE_DEVICE_TYPE(MC6854, mc6854_device) /* 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 transmitted. 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 // MAME_MACHINE_MC6854_H