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48 lines
1.4 KiB
C++
48 lines
1.4 KiB
C++
//
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// DiskIIDrive.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 20/11/2020.
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// Copyright © 2020 Thomas Harte. All rights reserved.
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//
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#include "DiskIIDrive.hpp"
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#include <bit>
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using namespace Apple::Disk;
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DiskIIDrive::DiskIIDrive(const int input_clock_rate) :
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IWMDrive(input_clock_rate, 1) {
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Drive::set_rotation_speed(300.0f);
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}
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void DiskIIDrive::set_enabled(const bool enabled) {
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set_motor_on(enabled);
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}
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void DiskIIDrive::set_control_lines(const int lines) {
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// If the stepper magnet selections have changed, and any is on, see how
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// that moves the head.
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if(lines ^ stepper_mask_ && lines) {
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// Convert from a representation of bits set to the centre of pull.
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int direction = 0;
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if(lines&1) direction += (((stepper_position_ - 0) + 4)&7) - 4;
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if(lines&2) direction += (((stepper_position_ - 2) + 4)&7) - 4;
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if(lines&4) direction += (((stepper_position_ - 4) + 4)&7) - 4;
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if(lines&8) direction += (((stepper_position_ - 6) + 4)&7) - 4;
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const int bits_set = std::popcount(uint8_t(lines));
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direction /= bits_set;
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// Compare to the stepper position to decide whether that pulls in the
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// current cog notch, or grabs a later one.
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step(Storage::Disk::HeadPosition(-direction, 4));
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stepper_position_ = (stepper_position_ - direction + 8) & 7;
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}
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stepper_mask_ = lines;
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}
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bool DiskIIDrive::read() {
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return !!(stepper_mask_ & 2) || is_read_only();
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}
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