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78 lines
1.7 KiB
C++
78 lines
1.7 KiB
C++
//
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// 6850.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 10/10/2019.
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// Copyright © 2019 Thomas Harte. All rights reserved.
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//
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#ifndef Motorola_ACIA_6850_hpp
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#define Motorola_ACIA_6850_hpp
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#include <cstdint>
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#include "../../ClockReceiver/ClockReceiver.hpp"
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#include "../../ClockReceiver/ClockingHintSource.hpp"
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#include "../SerialPort/SerialPort.hpp"
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namespace Motorola {
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namespace ACIA {
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class ACIA: public ClockingHint::Source {
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public:
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ACIA();
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/*!
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Reads from the ACIA.
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Bit 0 of the address is used as the ACIA's register select line —
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so even addresses select control/status registers, odd addresses
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select transmit/receive data registers.
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*/
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uint8_t read(int address);
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/*!
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Writes to the ACIA.
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Bit 0 of the address is used as the ACIA's register select line —
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so even addresses select control/status registers, odd addresses
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select transmit/receive data registers.
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*/
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void write(int address, uint8_t value);
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void run_for(HalfCycles);
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bool get_interrupt_line();
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// Input lines.
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Serial::Line receive;
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Serial::Line clear_to_send;
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Serial::Line data_carrier_detect;
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// Output lines.
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Serial::Line transmit;
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Serial::Line request_to_send;
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private:
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int divider_ = 1;
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enum class Parity {
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Even, Odd, None
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} parity_ = Parity::None;
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int data_bits_ = 7, stop_bits_ = 2;
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static const int NoTransmission = 0x100;
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int next_transmission_ = NoTransmission;
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void consider_transmission();
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bool receive_interrupt_enabled_ = false;
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bool transmit_interrupt_enabled_ = false;
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bool interrupt_request_ = false;
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ClockingHint::Preference preferred_clocking() final;
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};
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}
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}
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#endif /* Motorola_ACIA_6850_hpp */
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