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111 lines
2.9 KiB
C++
111 lines
2.9 KiB
C++
//
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// BD500.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 14/01/2020.
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// Copyright © 2020 Thomas Harte. All rights reserved.
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//
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#include "BD500.hpp"
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using namespace Oric;
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/*
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Notes on the code below: the Byte Drive 500 isn't well documented; this implementation is based on
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experimentation without access to real hardware as documented in http://forum.defence-force.org/viewtopic.php?f=25&t=2055
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and with additional guidance from iss of Oricutron (amongst other things) elsewhere,
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e.g. http://forum.defence-force.org/viewtopic.php?f=22&t=1698&start=105#p21468
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*/
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BD500::BD500() : DiskController(P1793, 9000000, Storage::Disk::Drive::ReadyType::ShugartModifiedRDY) {
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disable_basic_rom_ = true;
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select_paged_item();
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set_is_double_density(true);
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set_drive(1);
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}
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void BD500::write(int address, uint8_t value) {
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access(address);
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if(address >= 0x0320 && address <= 0x0323) {
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WD::WD1770::write(address, value);
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}
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if(address == 0x031a) {
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// Drive select; kudos to iss of Oricutron for figuring this one out;
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// cf. http://forum.defence-force.org/viewtopic.php?f=25&p=21409#p21393
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switch(value & 0xe0) {
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default: set_drive(0); break;
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case 0x20: set_drive(1); break;
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case 0x40: set_drive(2); break;
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case 0x80: set_drive(4); break;
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case 0xc0: set_drive(8); break;
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}
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}
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}
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uint8_t BD500::read(int address) {
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access(address);
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switch(address) {
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default: return 0xff;
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case 0x0320: case 0x0321: case 0x0322: case 0x0323:
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return WD::WD1770::read(address);
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case 0x312: return (get_data_request_line() ? 0x80 : 0x00) | (get_interrupt_request_line() ? 0x40 : 0x00);
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}
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}
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void BD500::access(int address) {
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// Determine whether to perform a command.
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switch(address) {
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case 0x0320: case 0x0321: case 0x0322: case 0x0323: case 0x0312:
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return;
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case 0x311: disable_basic_rom_ = true; break;
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case 0x313: enable_overlay_ram_ = false; break;
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case 0x314: enable_overlay_ram_ = true; break;
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case 0x317: disable_basic_rom_ = false; break;
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default: break;
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}
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select_paged_item();
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}
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void BD500::set_head_load_request(bool head_load) {
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// Turn all motors on or off; if off then unload the head instantly.
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is_loading_head_ |= head_load;
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for_all_drives([head_load] (Storage::Disk::Drive &drive, size_t) {
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drive.set_motor_on(head_load);
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});
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if(!head_load) set_head_loaded(false);
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}
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void BD500::run_for(const Cycles cycles) {
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// If a head load is in progress and the selected drive is now ready,
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// declare head loaded.
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if(is_loading_head_ && get_drive().get_is_ready()) {
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set_head_loaded(true);
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is_loading_head_ = false;
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}
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WD::WD1770::run_for(cycles);
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}
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void BD500::set_activity_observer(Activity::Observer *observer) {
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observer_ = observer;
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if(observer) {
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observer->register_led("BD-500");
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observer_->set_led_status("BD-500", get_head_loaded());
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}
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}
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void BD500::set_head_loaded(bool loaded) {
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WD::WD1770::set_head_loaded(loaded);
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if(observer_) {
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observer_->set_led_status("BD-500", loaded);
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}
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}
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