mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-19 08:31:11 +00:00
301 lines
8.8 KiB
C++
301 lines
8.8 KiB
C++
//
|
|
// Keyboard.h
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 08/05/2019.
|
|
// Copyright © 2019 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#ifndef Apple_Macintosh_Keyboard_hpp
|
|
#define Apple_Macintosh_Keyboard_hpp
|
|
|
|
#include "../../KeyboardMachine.hpp"
|
|
#include "../../../ClockReceiver/ClockReceiver.hpp"
|
|
|
|
#include <mutex>
|
|
#include <vector>
|
|
|
|
namespace Apple {
|
|
namespace Macintosh {
|
|
|
|
constexpr uint16_t KeypadMask = 0x100;
|
|
|
|
/*!
|
|
Defines the keycodes that could be passed directly to a Macintosh via set_key_pressed.
|
|
*/
|
|
enum class Key: uint16_t {
|
|
/*
|
|
See p284 of the Apple Guide to the Macintosh Family Hardware
|
|
for documentation of the mapping below.
|
|
*/
|
|
BackTick = 0x65,
|
|
k1 = 0x25, k2 = 0x27, k3 = 0x29, k4 = 0x2b, k5 = 0x2f,
|
|
k6 = 0x2d, k7 = 0x35, k8 = 0x39, k9 = 0x33, k0 = 0x3b,
|
|
|
|
Hyphen = 0x37,
|
|
Equals = 0x31,
|
|
Backspace = 0x67,
|
|
Tab = 0x61,
|
|
|
|
Q = 0x19, W = 0x1b, E = 0x1d, R = 0x1f, T = 0x23, Y = 0x21, U = 0x41, I = 0x45, O = 0x3f, P = 0x47,
|
|
A = 0x01, S = 0x03, D = 0x05, F = 0x07, G = 0x0b, H = 0x09, J = 0x4d, K = 0x51, L = 0x4b,
|
|
Z = 0x0d, X = 0x0f, C = 0x11, V = 0x13, B = 0x17, N = 0x5b, M = 0x5d,
|
|
|
|
OpenSquareBracket = 0x43,
|
|
CloseSquareBracket = 0x3d,
|
|
Semicolon = 0x53,
|
|
Quote = 0x4f,
|
|
Comma = 0x57,
|
|
FullStop = 0x5f,
|
|
ForwardSlash = 0x59,
|
|
|
|
CapsLock = 0x73,
|
|
Shift = 0x71,
|
|
Option = 0x75,
|
|
Command = 0x6f,
|
|
|
|
Space = 0x63,
|
|
Backslash = 0x55,
|
|
Return = 0x49,
|
|
|
|
Left = KeypadMask | 0x0d,
|
|
Right = KeypadMask | 0x05,
|
|
Up = KeypadMask | 0x1b,
|
|
Down = KeypadMask | 0x11,
|
|
|
|
KeypadDelete = KeypadMask | 0x0f,
|
|
KeypadEquals = KeypadMask | 0x11,
|
|
KeypadSlash = KeypadMask | 0x1b,
|
|
KeypadAsterisk = KeypadMask | 0x05,
|
|
KeypadMinus = KeypadMask | 0x1d,
|
|
KeypadPlus = KeypadMask | 0x0d,
|
|
KeypadEnter = KeypadMask | 0x19,
|
|
KeypadDecimalPoint = KeypadMask | 0x03,
|
|
|
|
Keypad9 = KeypadMask | 0x39,
|
|
Keypad8 = KeypadMask | 0x37,
|
|
Keypad7 = KeypadMask | 0x33,
|
|
Keypad6 = KeypadMask | 0x31,
|
|
Keypad5 = KeypadMask | 0x2f,
|
|
Keypad4 = KeypadMask | 0x2d,
|
|
Keypad3 = KeypadMask | 0x2b,
|
|
Keypad2 = KeypadMask | 0x29,
|
|
Keypad1 = KeypadMask | 0x27,
|
|
Keypad0 = KeypadMask | 0x25
|
|
};
|
|
|
|
class Keyboard {
|
|
public:
|
|
void set_input(bool data) {
|
|
switch(mode_) {
|
|
case Mode::Waiting:
|
|
/*
|
|
"Only the computer can initiate communication over the keyboard lines. When the computer and keyboard
|
|
are turned on, the computer is in charge of the keyboard interface and the keyboard is passive. The
|
|
computer signals that it is ready to begin communication by pulling the Keyboard Data line low."
|
|
*/
|
|
if(!data) {
|
|
mode_ = Mode::AcceptingCommand;
|
|
phase_ = 0;
|
|
command_ = 0;
|
|
}
|
|
break;
|
|
|
|
case Mode::AcceptingCommand:
|
|
/* Note value, so that it can be latched upon a clock transition. */
|
|
data_input_ = data;
|
|
break;
|
|
|
|
case Mode::AwaitingEndOfCommand:
|
|
/*
|
|
The last bit of the command leaves the Keyboard Data line low; the computer then indicates that it is ready
|
|
to receive the keyboard's response by setting the Keyboard Data line high.
|
|
*/
|
|
if(data) {
|
|
mode_ = Mode::PerformingCommand;
|
|
phase_ = 0;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
case Mode::SendingResponse:
|
|
/* This line isn't currently an input; do nothing. */
|
|
break;
|
|
}
|
|
}
|
|
|
|
bool get_clock() {
|
|
return clock_output_;
|
|
}
|
|
|
|
bool get_data() {
|
|
return !!(response_ & 0x80);
|
|
}
|
|
|
|
/*!
|
|
The keyboard expects ~10 µs-frequency ticks, i.e. a clock rate of just around 100 kHz.
|
|
*/
|
|
void run_for(HalfCycles) { // TODO: honour the HalfCycles argument.
|
|
switch(mode_) {
|
|
default:
|
|
case Mode::Waiting: return;
|
|
|
|
case Mode::AcceptingCommand: {
|
|
/*
|
|
"When the computer is sending data to the keyboard, the keyboard transmits eight cycles of 400 µS each (180 µS low,
|
|
220 µS high) on the Keyboard Clock line. On the falling edge of each keyboard clock cycle, the Macintosh Plus places
|
|
a data bit on the data line and holds it there for 400 µS. The keyboard reads the data bit 80 µS after the rising edge
|
|
of the Keyboard Clock signal."
|
|
*/
|
|
const auto offset = phase_ % 40;
|
|
clock_output_ = offset >= 18;
|
|
|
|
if(offset == 26) {
|
|
command_ = (command_ << 1) | (data_input_ ? 1 : 0);
|
|
}
|
|
|
|
++phase_;
|
|
if(phase_ == 8*40) {
|
|
mode_ = Mode::AwaitingEndOfCommand;
|
|
phase_ = 0;
|
|
clock_output_ = false;
|
|
}
|
|
} break;
|
|
|
|
case Mode::AwaitingEndOfCommand:
|
|
// Time out if the end-of-command seems not to be forthcoming.
|
|
// This is an elaboration on my part; a guess.
|
|
++phase_;
|
|
if(phase_ == 1000) {
|
|
clock_output_ = false;
|
|
mode_ = Mode::Waiting;
|
|
phase_ = 0;
|
|
}
|
|
return;
|
|
|
|
case Mode::PerformingCommand: {
|
|
response_ = perform_command(command_);
|
|
|
|
// Inquiry has a 0.25-second timeout; everything else is instant.
|
|
++phase_;
|
|
if(phase_ == 25000 || command_ != 0x10 || response_ != 0x7b) {
|
|
mode_ = Mode::SendingResponse;
|
|
phase_ = 0;
|
|
}
|
|
} break;
|
|
|
|
case Mode::SendingResponse: {
|
|
/*
|
|
"When sending data to the computer, the keyboard transmits eight cycles of 330 µS each (160 µS low, 170 µS high)
|
|
on the normally high Keyboard Clock line. It places a data bit on the data line 40 µS before the falling edge of each
|
|
clock cycle and maintains it for 330 µS. The VIA in the computer latches the data bit into its shift register on the
|
|
rising edge of the Keyboard Clock signal."
|
|
*/
|
|
const auto offset = phase_ % 33;
|
|
clock_output_ = offset >= 16;
|
|
|
|
if(offset == 29) {
|
|
response_ <<= 1;
|
|
}
|
|
|
|
++phase_;
|
|
if(phase_ == 8*33) {
|
|
clock_output_ = false;
|
|
mode_ = Mode::Waiting;
|
|
phase_ = 0;
|
|
}
|
|
} break;
|
|
}
|
|
}
|
|
|
|
void enqueue_key_state(uint16_t key, bool is_pressed) {
|
|
// Front insert; messages will be pop_back'd.
|
|
std::lock_guard lock(key_queue_mutex_);
|
|
|
|
// Keys on the keypad are preceded by a $79 keycode; in the internal naming scheme
|
|
// they are indicated by having bit 8 set. So add the $79 prefix if required.
|
|
if(key & KeypadMask) {
|
|
key_queue_.insert(key_queue_.begin(), 0x79);
|
|
}
|
|
key_queue_.insert(key_queue_.begin(), (is_pressed ? 0x00 : 0x80) | uint8_t(key));
|
|
}
|
|
|
|
private:
|
|
/// Performs the pre-ADB Apple keyboard protocol command @c command, returning
|
|
/// the proper result if the command were to terminate now. So, it treats inquiry
|
|
/// and instant as the same command.
|
|
int perform_command(int command) {
|
|
switch(command) {
|
|
case 0x10: // Inquiry.
|
|
case 0x14: { // Instant.
|
|
std::lock_guard lock(key_queue_mutex_);
|
|
if(!key_queue_.empty()) {
|
|
const auto new_message = key_queue_.back();
|
|
key_queue_.pop_back();
|
|
return new_message;
|
|
}
|
|
} break;
|
|
|
|
case 0x16: // Model number.
|
|
return
|
|
0x01 | // b0: always 1
|
|
(1 << 1) | // keyboard model number
|
|
(1 << 4); // next device number
|
|
// (b7 not set => no next device)
|
|
|
|
case 0x36: // Test
|
|
return 0x7d; // 0x7d = ACK, 0x77 = not ACK.
|
|
}
|
|
return 0x7b; // No key transition.
|
|
}
|
|
|
|
/// Maintains the current operating mode — a record of what the
|
|
/// keyboard is doing now.
|
|
enum class Mode {
|
|
/// The keyboard is waiting to begin a transaction.
|
|
Waiting,
|
|
/// The keyboard is currently clocking in a new command.
|
|
AcceptingCommand,
|
|
/// The keyboard is waiting for the computer to indicate that it is ready for a response.
|
|
AwaitingEndOfCommand,
|
|
/// The keyboard is in the process of performing the command it most-recently received.
|
|
/// If the command was an 'inquiry', this state may persist for a non-neglibible period of time.
|
|
PerformingCommand,
|
|
/// The keyboard is currently shifting a response back to the computer.
|
|
SendingResponse,
|
|
} mode_ = Mode::Waiting;
|
|
|
|
/// Holds a count of progress through the current @c Mode. Exact meaning depends on mode.
|
|
int phase_ = 0;
|
|
/// Holds the most-recently-received command; the command is shifted into here as it is received
|
|
/// so this may not be valid prior to Mode::PerformingCommand.
|
|
int command_ = 0;
|
|
/// Populated during PerformingCommand as the response to the most-recently-received command, this
|
|
/// is then shifted out to the host computer. So it is guaranteed valid at the beginning of Mode::SendingResponse,
|
|
/// but not afterwards.
|
|
int response_ = 0;
|
|
|
|
/// The current state of the serial connection's data input.
|
|
bool data_input_ = false;
|
|
/// The current clock output from this keyboard.
|
|
bool clock_output_ = false;
|
|
|
|
/// Guards multithread access to key_queue_.
|
|
std::mutex key_queue_mutex_;
|
|
/// A FIFO queue for key events, in the form they'd be communicated to the Macintosh,
|
|
/// with the newest events towards the front.
|
|
std::vector<uint8_t> key_queue_;
|
|
};
|
|
|
|
/*!
|
|
Provides a mapping from idiomatic PC keys to Macintosh keys.
|
|
*/
|
|
class KeyboardMapper: public MachineTypes::MappedKeyboardMachine::KeyboardMapper {
|
|
uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) const final;
|
|
};
|
|
|
|
}
|
|
}
|
|
|
|
#endif /* Apple_Macintosh_Keyboard_hpp */
|