mirror of https://github.com/TomHarte/CLK.git
111 lines
2.5 KiB
C++
111 lines
2.5 KiB
C++
//
|
|
// z8530.hpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 07/06/2019.
|
|
// Copyright © 2019 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#pragma once
|
|
|
|
#include <cstdint>
|
|
|
|
namespace Zilog::SCC {
|
|
|
|
/*!
|
|
Models the Zilog 8530 SCC, a serial adaptor.
|
|
*/
|
|
class z8530 {
|
|
public:
|
|
/*
|
|
**Interface for emulated machine.**
|
|
|
|
Notes on addressing below:
|
|
|
|
There's no inherent ordering of the two 'address' lines,
|
|
A/B and C/D, but the methods below assume:
|
|
|
|
A/B = A0
|
|
C/D = A1
|
|
*/
|
|
|
|
/// Performs a read from the SCC; see above for conventions as to 'address'.
|
|
std::uint8_t read(int address);
|
|
/// Performs a write to the SCC; see above for conventions as to 'address'.
|
|
void write(int address, std::uint8_t value);
|
|
/// Resets the SCC.
|
|
void reset();
|
|
|
|
/// @returns The current value of the status output: @c true for active; @c false for inactive.
|
|
bool get_interrupt_line() const;
|
|
|
|
struct Delegate {
|
|
/*!
|
|
Communicates that @c scc now has the interrupt line status @c new_status.
|
|
*/
|
|
virtual void did_change_interrupt_status(z8530 *scc, bool new_status) = 0;
|
|
};
|
|
|
|
/*!
|
|
Sets the delegate for this SCC. If this is a new delegate it is sent
|
|
an immediate did_change_interrupt_status message, to get it
|
|
up to speed.
|
|
*/
|
|
void set_delegate(Delegate *delegate) {
|
|
if(delegate_ == delegate) return;
|
|
delegate_ = delegate;
|
|
delegate_->did_change_interrupt_status(this, get_interrupt_line());
|
|
}
|
|
|
|
/*
|
|
**Interface for serial port input.**
|
|
*/
|
|
void set_dcd(int port, bool level);
|
|
|
|
private:
|
|
class Channel {
|
|
public:
|
|
uint8_t read(bool data, uint8_t pointer);
|
|
void write(bool data, uint8_t pointer, uint8_t value);
|
|
void set_dcd(bool level);
|
|
bool get_interrupt_line() const;
|
|
|
|
private:
|
|
uint8_t data_ = 0xff;
|
|
|
|
enum class Parity {
|
|
Even, Odd, Off
|
|
} parity_ = Parity::Off;
|
|
|
|
enum class StopBits {
|
|
Synchronous, OneBit, OneAndAHalfBits, TwoBits
|
|
} stop_bits_ = StopBits::Synchronous;
|
|
|
|
enum class Sync {
|
|
Monosync, Bisync, SDLC, External
|
|
} sync_mode_ = Sync::Monosync;
|
|
|
|
int clock_rate_multiplier_ = 1;
|
|
|
|
uint8_t interrupt_mask_ = 0; // i.e. Write Register 0x1.
|
|
|
|
uint8_t external_interrupt_mask_ = 0; // i.e. Write Register 0xf.
|
|
bool external_status_interrupt_ = false;
|
|
uint8_t external_interrupt_status_ = 0;
|
|
|
|
bool dcd_ = false;
|
|
} channels_[2];
|
|
|
|
uint8_t pointer_ = 0;
|
|
|
|
uint8_t interrupt_vector_ = 0;
|
|
|
|
uint8_t master_interrupt_control_ = 0;
|
|
|
|
bool previous_interrupt_line_ = false;
|
|
void update_delegate();
|
|
Delegate *delegate_ = nullptr;
|
|
};
|
|
|
|
}
|