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CLK/Machines/Acorn/Archimedes/Keyboard.hpp
2024-04-06 21:24:21 -04:00

241 lines
7.2 KiB
C++

//
// Keyboard.hpp
// Clock Signal
//
// Created by Thomas Harte on 20/03/2024.
// Copyright © 2024 Thomas Harte. All rights reserved.
//
#pragma once
#include "HalfDuplexSerial.hpp"
#include "../../../Outputs/Log.hpp"
#include "../../../Inputs/Mouse.hpp"
namespace Archimedes {
// Resource for the keyboard protocol: https://github.com/tmk/tmk_keyboard/wiki/ACORN-ARCHIMEDES-Keyboard
struct Keyboard {
Keyboard(HalfDuplexSerial &serial) : serial_(serial), mouse_(*this) {}
void set_key_state(int row, int column, bool is_pressed) {
if(!scan_keyboard_) {
logger_.info().append("Ignored key event as key scanning disabled");
return;
}
// Don't waste bandwidth on repeating facts.
if(states_[row][column] == is_pressed) return;
states_[row][column] = is_pressed;
// Post new key event.
logger_.info().append("Posting row %d, column %d is now %s", row, column, is_pressed ? "pressed" : "released");
const uint8_t prefix = is_pressed ? 0b1100'0000 : 0b1101'0000;
enqueue(static_cast<uint8_t>(prefix | row), static_cast<uint8_t>(prefix | column));
consider_dequeue();
}
void update() {
if(serial_.events(KeyboardParty) & HalfDuplexSerial::Receive) {
const auto reset = [&]() {
serial_.output(KeyboardParty, HRST);
state_ = State::Idle;
};
const uint8_t input = serial_.input(KeyboardParty);
// A reset command is always accepted, usurping any other state.
if(input == HRST) {
logger_.info().append("HRST; resetting");
state_ = State::ExpectingRAK1;
event_queue_.clear();
serial_.output(KeyboardParty, HRST);
return;
}
switch(state_) {
case State::ExpectingACK:
if(input != NACK && input != SMAK && input != MACK && input != SACK) {
logger_.error().append("No ack; requesting reset");
reset();
break;
}
state_ = State::Idle;
[[fallthrough]];
case State::Idle:
switch(input) {
case RQID: // Post keyboard ID.
serial_.output(KeyboardParty, 0x81); // Declare this to be a UK keyboard.
logger_.info().append("RQID; responded with 0x81");
break;
case PRST: // "1-byte command, does nothing."
logger_.info().append("PRST; ignored");
break;
case RQMP:
logger_.error().append("RQMP; TODO: respond something other than 0, 0");
enqueue(0, 0);
break;
case NACK: case SMAK: case MACK: case SACK:
scan_keyboard_ = input & 1;
scan_mouse_ = input & 2;
logger_.info().append("ACK; keyboard:%d mouse:%d", scan_keyboard_, scan_mouse_);
break;
default:
if((input & 0b1111'0000) == 0b0100'0000) {
// RQPD; request to echo the low nibble.
serial_.output(KeyboardParty, 0b1110'0000 | (input & 0b1111));
logger_.info().append("RQPD; echoing %x", input & 0b1111);
} else if(!(input & 0b1111'1000)) {
// LEDS: should set LED outputs.
logger_.error().append("TODO: set LEDs %d%d%d", static_cast<bool>(input&4), static_cast<bool>(input&2), static_cast<bool>(input&1));
} else {
logger_.info().append("Ignoring unrecognised command %02x received in idle state", input);
}
break;
}
break;
case State::ExpectingRAK1:
if(input != RAK1) {
logger_.info().append("Didn't get RAK1; resetting");
reset();
break;
}
logger_.info().append("Got RAK1; echoing");
serial_.output(KeyboardParty, input);
state_ = State::ExpectingRAK2;
break;
case State::ExpectingRAK2:
if(input != RAK2) {
logger_.info().append("Didn't get RAK2; resetting");
reset();
break;
}
logger_.info().append("Got RAK2; echoing");
serial_.output(KeyboardParty, input);
state_ = State::ExpectingACK;
break;
case State::ExpectingBACK:
if(input != BACK) {
logger_.info().append("Didn't get BACK; resetting");
reset();
break;
}
logger_.info().append("Got BACK; posting next byte");
dequeue_next();
state_ = State::ExpectingACK;
break;
}
}
consider_dequeue();
}
void consider_dequeue() {
if(state_ == State::Idle) {
// If the key event queue is empty, grab as much mouse motion
// as available.
if(event_queue_.empty()) {
const int x = std::clamp(mouse_x_, -0x3f, 0x3f);
const int y = std::clamp(mouse_y_, -0x3f, 0x3f);
mouse_x_ -= x;
mouse_y_ -= y;
if(x || y) {
enqueue(static_cast<uint8_t>(x) & 0x7f, static_cast<uint8_t>(-y) & 0x7f);
}
}
if(dequeue_next()) {
state_ = State::ExpectingBACK;
}
}
}
Inputs::Mouse &mouse() {
return mouse_;
}
private:
HalfDuplexSerial &serial_;
Log::Logger<Log::Source::Keyboard> logger_;
bool states_[16][16]{};
bool scan_keyboard_ = false;
bool scan_mouse_ = false;
enum class State {
ExpectingRAK1, // Post a RAK1 and proceed to ExpectingRAK2 if RAK1 is received; otherwise request a reset.
ExpectingRAK2, // Post a RAK2 and proceed to ExpectingACK if RAK2 is received; otherwise request a reset.
ExpectingACK, // Process NACK, SACK, MACK or SMAK if received; otherwise request a reset.
Idle, // Process any of: NACK, SACK, MACK, SMAK, RQID, RQMP, RQPD or LEDS if received; also
// unilaterally begin post a byte pair enqueued but not yet sent if any are waiting.
ExpectingBACK, // Dequeue and post one further byte if BACK is received; otherwise request a reset.
} state_ = State::Idle;
std::vector<uint8_t> event_queue_;
void enqueue(uint8_t first, uint8_t second) {
event_queue_.push_back(first);
event_queue_.push_back(second);
}
bool dequeue_next() {
// To consider: a cheaper approach to the queue than this; in practice events
// are 'rare' so it's not high priority.
if(event_queue_.empty()) return false;
serial_.output(KeyboardParty, event_queue_[0]);
event_queue_.erase(event_queue_.begin());
return true;
}
static constexpr uint8_t HRST = 0b1111'1111; // Keyboard reset.
static constexpr uint8_t RAK1 = 0b1111'1110; // Reset response #1.
static constexpr uint8_t RAK2 = 0b1111'1101; // Reset response #2.
static constexpr uint8_t RQID = 0b0010'0000; // Request for keyboard ID.
static constexpr uint8_t RQMP = 0b0010'0010; // Request for mouse data.
static constexpr uint8_t BACK = 0b0011'1111; // Acknowledge for first keyboard data byte pair.
static constexpr uint8_t NACK = 0b0011'0000; // Acknowledge for last keyboard data byte pair, disables both scanning and mouse.
static constexpr uint8_t SACK = 0b0011'0001; // Last data byte acknowledge, enabling scanning but disabling mouse.
static constexpr uint8_t MACK = 0b0011'0010; // Last data byte acknowledge, disabling scanning but enabling mouse.
static constexpr uint8_t SMAK = 0b0011'0011; // Last data byte acknowledge, enabling scanning and mouse.
static constexpr uint8_t PRST = 0b0010'0001; // Does nothing.
struct Mouse: public Inputs::Mouse {
Mouse(Keyboard &keyboard): keyboard_(keyboard) {}
void move(int x, int y) override {
keyboard_.mouse_x_ += x;
keyboard_.mouse_y_ += y;
}
int get_number_of_buttons() override {
return 3;
}
virtual void set_button_pressed(int index, bool is_pressed) override {
keyboard_.set_key_state(7, index, is_pressed);
}
private:
Keyboard &keyboard_;
};
Mouse mouse_;
int mouse_x_ = 0;
int mouse_y_ = 0;
};
}