This document describes the observable behavior of the RCBus desktop application and its bundled emulated hardware. A reimplementation may use any language or UI framework. Names of libraries and implementation classes are not requirements; byte-level protocols, hardware behavior, user workflows, and persisted settings are. Where the current implementation is incomplete, the limitation is recorded rather than silently specifying a new behavior.
- The application shall provide three navigable views: serial terminal, RCBus emulator, and settings/about. No view is selected on first launch; only the subsequently selected view is visible. Selecting an already active serial or emulator view toggles its configuration panel; the terminal occupies the remaining width. Each configuration panel can also be resized, with separate persisted widths (360 by default).
- On startup, the saved theme shall be applied before the main UI appears. Light and dark themes are selectable; without a saved theme, the platform default is used. The settings view shall display application title, version, author, copyright, description, and icon credit from application metadata.
- Reset settings shall clear saved application settings and request the platform-default theme. It does not erase emulator disk images or program files.
- The desktop application shall use a writable per-user
Retroworks.RCBusapplication-data directory for its settings and daily rolling log. Unhandled exceptions shall be logged; on Windows the current crash-report path launches a separate window showing cause, exception type, message, stack trace, and an OK action. The launcher constructs an.exepath from the assembly path, so the crash window is not verified on macOS; packaging support must not be taken as proof that it works there.
- The desktop project targets Windows x86/x64 and macOS Intel (
osx-x64) and Apple Silicon (osx-arm64). A macOS build shall provide a native-architecture.appbundle inside an architecture-specific DMG, alongside an Applications-folder shortcut. The declared minimum macOS version is 10.15. These are build/package targets, not evidence that all runtime paths have been exercised on each platform. - The macOS packaging workflow publishes a self-contained Release build and names each output
Retroworks-RCBus-<version>-<runtime>.dmg, for exampleRetroworks-RCBus-0.1.0-osx-arm64.dmg. The convenience build for both architectures produces two separate DMGs, not a single universal app binary. The bundle executable isRetroworks.RCBus; the application identifier iscom.capnode.retroworks.rcbus, and the package version is0.1.0(distinct from the About page's displayed assembly version0.1.0.0). A replacement need not use the same build tools but shall preserve the architecture-specific installable application and version/identity information when reproducing this distribution workflow. - The project declares macOS serial-device and USB entitlements, but the DMG script does not sign or notarize its output. Do not assume that declaring entitlements grants device access in an unsigned package. The current macOS packaging path does not establish working file-type associations or additional privacy permissions; a separate plist template exists but is not used by the packaging script.
| Starting state / action | Result |
|---|---|
| New process, before choosing a page | Navigation rail visible; no content page selected; serial and emulator power off; both configuration panels initially expanded. |
| Choose Serial, Emulator, or Settings | Only that page is visible; the other connections are not implicitly stopped. |
| Choose the already selected Serial or Emulator page | Toggle that page's configuration panel between its saved width and zero; do not toggle power. |
| Choose an unselected page, then return to a connection page | Preserve the connection and that page's terminal and panel expansion state. |
| Serial Power with no port or no saved configuration for the selected port | No connection, no new powered state. |
| Serial Power with configured port / Power again | Open port and create a fresh terminal / close port, turn off indicator, clear terminal. |
| Emulator Power with no profile / selected profile | Do nothing / create a fresh terminal and start the selected machine asynchronously. |
| Emulator Power while running / CPU completes | Request stop and clear terminal / turn off indicator, leave completion message and terminal visible. |
| Settings Reset | Clear stored keys and request the platform theme; existing program and disk files remain untouched. |
The navigation controls are icon buttons with tooltips; serial and emulator pages have a power button, selection controls, a resizable left panel, and a terminal to the right. Emulator inputs are switches below their LEDs, with output LEDs above. Settings has Settings (reset and theme) and About (metadata and icon credit) tabs. The desktop window title is Retroworks RCBus. Current About values are title Retroworks.RCBus, displayed assembly version 0.1.0.0, author/company Capnode AB, copyright notice U+00A9 followed by 2025, description RCBus toolkit with VT100 terminal for emulator and serial port., and credit Retro icons created by Darius Dan - Flaticon.com. These are functional/layout requirements, not a promise of pixel-identical fonts or licensed icon assets.
- The serial view shall enumerate available operating-system ports on entry and refresh the list when the port selector opens. It shall allow selection of a port, baud rate (110, 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 38400, 57600, 115200, 230400, 460800, 921600), 7 or 8 data bits, parity, stop bits, flow control, and transmission delays in milliseconds per character and per carriage return.
- Serial settings shall be persisted separately for each port, together with the last selected port. An unconfigured port cannot be powered on. While connected, port and framing selectors are disabled. Power toggles opening and closing the port and clears the terminal on disconnect.
- The opened port shall use the chosen framing/handshake, enabled RTS and DTR, CRLF as its newline, 4096-byte read/write buffers, and 1500 ms read/write timeouts. Incoming bytes shall be forwarded to the terminal unchanged. Outgoing bytes shall be sent in order, either as one write when no delay applies or byte by byte with the configured character delay, substituting the line delay after CR (
0x0D).
- Settings shall include theme, selected serial port, per-port serial configuration, selected emulator profile, per-profile program and CompactFlash paths, per-profile digital input byte, and both panel widths. Per-port serial configuration is stored as a JSON object with
PortName,Speed,Parity,DataBit,StopBit,Handshake,TxCharDelay, andTxLineDelayfields. - A profile's program and CompactFlash file selectors shall accept one local file each and display the selected basename while retaining the full path. Settings changes shall survive application restart.
| Key | Value / fallback |
|---|---|
Theme |
Light or Dark; absent means platform theme. |
SerialPort |
Last selected OS port name; absent means no selection. |
<port name> |
JSON with fields PortName, Speed, Parity, DataBit, StopBit, Handshake, TxCharDelay, TxLineDelay; values are port name and numeric settings. |
DeviceName |
Last selected machine profile; absent means no selection. |
<profile>:ProgramPath, <profile>:CfPath |
Local paths; absent means no file. |
<profile>:InPort |
Decimal string from 0 to 255; absent is interpreted as 0 when selecting the profile. |
SerialPanelWidth, EmulatorPanelWidth |
Width in UI units; absent or invalid values fall back to 360. |
Selecting a port with no saved JSON clears its displayed serial parameters to zero/enum defaults; the UI does not automatically apply the model's standalone 9600/8/N/1 defaults. Changing a serial parameter saves its port JSON immediately. Refreshing to an empty OS port list clears the current UI port selection. Input switch changes, theme changes, file choices and panel resizing are saved when made. Reset clears persisted values but does not automatically reload already visible selections and fields; a restart restores their absent-key defaults. A reimplementation need not use user.config, but must preserve these logical keys and round-trip behaviors if importing existing settings.
For compatibility with the existing serialized form, enum fields use numeric values: parity None=0, Odd=1, Even=2, Mark=3, Space=4; stop bits None=0, One=1, Two=2, OnePointFive=3; handshake None=0, XOnXOff=1, RequestToSend=2, RequestToSendXOnXOff=3. For example, a 9600/8/N/1 port with no handshake or transmit delays may be stored under its port-name key as:
{"PortName":"COM7","Speed":9600,"Parity":0,"DataBit":8,"StopBit":1,"Handshake":0,"TxCharDelay":0,"TxLineDelay":0}JSON property order and whitespace are not meaningful. The serial-port implementation sets RTS and DTR even when the selected handshake is None; it uses CRLF for the port's NewLine setting, while terminal keystrokes such as Enter still transmit the single byte 0D.
- Both connection views shall have a separate resizable, scrollable VT100/XTerm-style terminal. Incoming connection bytes shall be parsed incrementally, including escape/control sequences split across reads. The screen shall handle cursor movement, scrolling/history, character sets, text attributes (including 16-color and RGB colors, bold, underline, blink, conceal, reverse video), and double-width/double-height rows. Terminal-generated responses and keyboard sequences shall be sent back through the active connection. The portable acceptance subset and byte sequences are specified below; full compatibility with every XTerm extension is not established by this document.
- A new connection shall create a new terminal. Its default colors are black text on white in the light theme and green text on black otherwise. Terminal resizing shall resize its character grid based on the available area and monospaced glyph dimensions; there is currently no serial or emulator-side window-size protocol.
- Keyboard input shall be translated according to the terminal's active cursor-key mode. Mouse tracking shall forward pointer events when enabled by the terminal protocol; otherwise, left-button drag selects text and copies it to the clipboard and right click pastes clipboard text as UTF-8 bytes. Wheel scrolling navigates terminal history; Ctrl+wheel changes terminal font size, clamped to 2-20. The cursor shall reflect focus and blink. Ctrl+F10/F11/F12 toggle sequence, view, and terminal debugging respectively.
Here ESC means byte 1B, CSI means ESC [ (1B 5B), and terminal input and output are byte streams, not lines. Process partial escape sequences across incoming chunks. The following is the minimum independently testable subset, not a claim that every XTerm sequence is covered:
| Input / action | Expected effect or outbound bytes |
|---|---|
41 42 43 (ABC) |
Display ABC in successive cells. |
ESC [ 2 J (1B 5B 32 4A) |
Clear displayed screen; subsequent printable bytes render on the cleared screen. |
ESC [ 2 ; 3 H |
Place cursor at row 2, column 3 (one-based); next printed character occupies that cell. |
ESC [ 31 m then 41, then ESC [ 0 m |
Render A in red, reset following text to default attributes. |
ESC [ ? 1 h then Up key |
Enable application cursor-key mode; send 1B 4F 41 instead of normal 1B 5B 41. ESC [ ? 1 l restores normal mode. |
| Enter, Backspace, Shift+Tab, Escape, Ctrl+A | Send respectively 0D, 08, 1B 5B 5A, 1B 1B, 01. The double-ESC mapping is the existing keyboard behavior, not a VT standard assumption. |
| F1, F5, Delete | Send respectively 1B 4F 50, 1B 5B 31 35 7E, 1B 5B 33 7E. |
Paste the string A followed by U+00E9 |
Send UTF-8 bytes 41 C3 A9; do not translate pasted text through the key map. |
CSI SGR attributes include foreground/background indexed colors, bright colors and 24-bit RGB, as well as bold, underline, blink, conceal and inverse. Ordinary keyboard characters are sent as UTF-8; an incoming byte stream is decoded according to the terminal's currently selected character encoding. Font size starts at 20 UI units; the user can scroll history or change font size with Ctrl+wheel without changing connection settings. Do not substitute line-oriented input for incremental escape parsing.
- The emulator view shall offer profiles
SCM-F1,SCM-F2,SCM-S2,SCM-S3,SCM-S7, andSCM-S8. A profile must be selected before powering on. While running, profile and file selectors are disabled. Power-on initializes the selected machine, optionally loads a program, then starts its Z80 processor on a background execution path. Power-off requests cancellation and clears the terminal; natural completion or failure reportsExecution CompletedorError: ...in the terminal and turns off the power indicator. The current implementation does not clear the terminal on natural completion. - A selected program whose filename ends in
.hex(case insensitive) is interpreted as Intel HEX. Only record types00(data) and01(end) are processed:00writes each byte to the current memory mapping at the record's 16-bit address;01stops reading. Lines without a leading colon are ignored. Other record types are ignored; extended addresses and checksums are not interpreted or verified. No selected program means execution starts with initialized, zero-filled memory. - Any other program filename is loaded as raw binary in file order, in 256-byte chunks, across consecutive 32 KiB banks of the 1 MiB memory. The loader stops before a chunk that would exceed memory, reports that the file is too large, restores bank zero, and reports the number of bytes actually loaded. Missing program files are reported in the terminal and do not prevent CPU start. Successful loads report the basename and loaded byte count.
- Terminal bytes sent to a running emulator shall be passed in order to its ACIA receiver; bytes transmitted by the emulated ACIA shall appear on the same terminal. A file chosen as a CompactFlash image is only used by profiles that actually attach IDE (currently
SCM-S7).
| Profile | ACIA control/data | Digital I/O | IDE registers | ACIA interrupt source |
|---|---|---|---|---|
| SCM-F1, SCM-F2 | 0xA2 / 0xA3 |
0xA0 |
none | no |
| SCM-S2, SCM-S3, SCM-S8 | 0x80 / 0x81 |
0x00 |
none | no |
| SCM-S7 | 0x80 / 0x81 |
0x00 |
0x10-0x17 |
yes |
- All six profiles shall run a Z80-compatible processor configured for 7.3728 MHz with a 256-port I/O space, 1 MiB of memory in 32 KiB banks, and a bank control at ports
0x78and0x79. The CPU begins at address0x0000after reset, executes standard Z80 machine instructions with their documented register, flag, stack, I/O and interrupt effects, and stops on cancellation or its normal stop conditions. Exact cycle timing relative to wall-clock time and the undocumented-instruction subset have not been verified; neither should be inferred from the nominal clock frequency. - Addresses
0x0000-0x7FFFshall select a 32 KiB bank (bank * 0x8000 + address). Addresses0x8000-0xFFFFshall map to the shared upper 32 KiB at physical addresses0xF8000-0xFFFFF, independent of bank selection. Writing either bank port selectsvalue >> 1; memory starts at bank zero. Unhandled I/O reads yield0xFF. Reads from multiple devices at a port are combined by bitwise AND; writes are broadcast to mapped devices. - The digital I/O port shall return an eight-bit input value on read and update eight output indicators on write. The UI shall offer eight input switches with red input indicators and eight green output indicators, displayed from bit 7 at the left to bit 0 at the right. Switching inputs shall update the emulated input byte and persist its decimal value for that profile; restoring that profile shall restore the input switches and byte.
- The ACIA 6850 interface shall expose status/control at its base port and receive/transmit data at base+1. A control write with low two bits set (
value & 3 == 3) resets status; other control writes set transmitter-empty status (0x02). A data write transmits one byte and sets transmitter-empty. Incoming bytes queue in arrival order and set receiver-full (0x01); when receive interrupt is enabled by control bit 7, they also assert interrupt/status bit 7. Data reads dequeue the next byte; when the queue empties, receiver-full and interrupt are cleared. OnlySCM-S7registers the ACIA as a CPU interrupt source. This specifies the implemented subset, not every feature of a physical 6850. - On
SCM-S7, an IDE device at0x10-0x17exposes the conventional data, error/features, sector count, sector number, cylinder low/high, drive/head, and status/command register offsets. Only drive 0 is connected; selecting another drive returns0xFFon all register reads and ignores writes except to drive/head (which permits reselecting drive 0). At initialization status is ready and seek-complete (0x50). The implementedIDENTIFY DEVICE(0xEC) populates a 512-byte identity block using geometry 1986 cylinders, 16 heads, 63 sectors/track and sets data-request; reading data drains that block and clears data-request.SET FEATURES(0xEF) recognizes feature values0x01and0x03. Although command constants exist for sector I/O and other ATA commands, their behavior is not implemented; do not infer functional disk reads/writes from those constants. - For
SCM-S7, an existing CompactFlash path is opened for read/write; a missing path is created as a 1 GiB file. No path means no backing file is opened. The image is currently not read or written by the implemented IDE command handlers.
All hex numbers below are bytes unless an address or a 16-bit word is explicitly named. A fresh machine starts with zeroed RAM and bank 0. The shared upper RAM starts at physical 0xF8000. For example, a write of 5A at CPU address 0x0000 in bank 0 changes physical 0x00000; after writing 03 to I/O port 0x78, the selected bank is 1 and a write of A5 at 0x0000 changes physical 0x08000 without changing bank 0. A write of 66 at CPU address 0x8000 changes physical 0xF8000 and remains visible after any bank switch. Port 0x79 has the same bank-select effect as 0x78. The 0x8000 boundary is shared RAM, not part of the selected bank. Bank 31's lower window also maps to physical 0xF8000-0xFFFFF, aliasing the shared upper RAM.
For each profile's ACIA base port P, the following sequence is reproducible through its registers before running CPU code:
| Action | Expected status at P; read at P+1 if applicable |
|---|---|
| Fresh ACIA | 00 |
Write 80 to P (enable receive interrupt) |
02 (transmitter empty) |
Deliver incoming bytes 41, 42 |
83 (receiver full, transmitter empty, interrupt asserted) |
Read P+1 once |
Returns 41; status still 83 because 42 remains queued |
Read P+1 again |
Returns 42; status becomes 02, interrupt deasserted |
Write 55 to P+1 |
Transmit 55 to terminal; status retains transmitter-empty bit 02 |
Write 03 to P |
Master reset clears status to 00 |
The receiver queue is not cleared by a control-register master reset in the current implementation. An empty data read returns the last received data byte (initially 00), not a new byte. This is an implemented subset; no ACIA framing, handshaking, baud-clock, carrier, or overrun behavior is modeled. On SCM-S7 only, receive interrupt state is also wired into the Z80 interrupt-source interface.
For the digital port D, selecting a profile without a saved <profile>:InPort sets the visible input byte to 00. Turning on only input switches 8 and 1 writes 81 to the input latch and persists decimal 129; a CPU read from D returns 81. A CPU write of A5 to D illuminates only output LEDs 8, 6, 3 and 1 (bits 7, 5, 2 and 0). Other I/O addresses without responding devices read FF.
The SCM-S7 IDE subset uses register offsets 0 data, 1 error/features, 2 sector count, 3 sector number, 4 cylinder low, 5 cylinder high, 6 drive/head and 7 status/command, relative to 0x10. At start, reading 0x17 gives 50. Writing 10 to drive/head 0x16 selects drive 1 and makes reads at 0x10-0x17 yield FF; writing 00 to 0x16 selects drive 0 again. Writing EC to 0x17 (IDENTIFY) yields status 58, then 512 successive reads of 0x10 return the identity block and leave status 50. A data read beyond the block repeats the last data byte; sector read (20) and write (30) commands do not transfer image data.
The IDENTIFY data is 256 little-endian 16-bit words. Initialize the 512-byte block to zero, then set the following words (indices are decimal). Values not listed remain zero:
| Word indices | Values (hex unless stated otherwise) |
|---|---|
| 0, 1, 3, 5, 6 | 848A, 07C2 (1986 cylinders), 0010 (16 heads), 0240 (576), 003F (63 sectors/track) |
| 7, 8 | 001E, 8BE0 (total sectors 0x001E8BE0 = 2,001,888) |
| 20, 21, 22, 47 | 0002, 0002, 0004, 0004 |
| 49, 51, 53 | 0300, 0200, 0003 |
| 54, 55, 56, 57, 58, 59, 60, 61 | 07C2, 0010, 003F, 8BE0, 001E, 0100, 8BE0, 001E |
| 63, 64, 65-68, 80 | 0007, 0003, 0078 for each of 65-68, 0010 |
| 83, 84, 86, 87 | 4004, 4000, 0004, 4000 |
After populating the words, overwrite bytes 20-39 (words 10-19) with ASCII 1060512B03M93035, bytes 46-53 (words 23-26) with ASCII DH X.423, and bytes 54-93 (words 27-46) with ASCII aSDnsi kDSFC-J0142 followed by spaces to 40 bytes. The first eight identity bytes must therefore be 8A 84 C2 07 00 00 10 00, and bytes 120-123 (words 60-61) must be E0 8B 1E 00. This describes the existing identity reply, not a complete ATA device.
| Input to a newly initialized machine | Required effect before CPU execution |
|---|---|
| No program path | RAM remains zero; CPU still starts. |
Empty .bin |
Report Loaded 0 bytes; start with zero RAM and bank 0. |
Binary with 32,769 bytes: first byte 11, byte at offset 32,767 22, byte at offset 32,768 33 |
Bank 0 0x0000 = 11, bank 0 0x7FFF = 22, bank 1 0x0000 = 33; report Loaded 32769 bytes; restore bank 0. |
| Binary of exactly 1,048,576 bytes | Load all 32 lower banks, report Loaded 1048576 bytes, restore bank 0; the last 32 KiB (bank 31) also overwrites shared upper RAM through its physical alias. |
| Binary of 1,048,577 bytes | Load first 1,048,576 bytes; report File too large for memory (1048577 bytes) and Loaded 1048576 bytes; restore bank 0. |
.hex containing :030000003E41C9B5 then :00000001FF |
Write 3E 41 C9 to bank 0 CPU addresses 0000-0002; report Loaded 3 bytes. |
.hex containing :01800000AAD5 then :00000001FF |
Write AA to shared RAM CPU address 8000 (physical 0xF8000); report Loaded 1 bytes. |
.hex containing :020000040001F9 then :00000001FF |
Ignore extended-linear-address record; report Loaded 0 bytes. |
| Missing selected file | Report The file '<path>' does not exist. followed by CRLF, then start CPU anyway. |
HEX counts refer only to data-record payload bytes. Record checksums are not checked, so changing a checksum alone does not change what is written. Other record types, including extended-address records, are ignored, not applied to later data addresses. Both successful loader messages (Loading '<basename>' and Loaded N bytes) are terminated by CRLF (0D 0A); malformed record fields instead fault the asynchronous emulator task and generate an Error: ... message. The paths and filenames in these messages come from the chosen local file.
- The requirements above describe the observable implementation, not the full RCBus hardware standard. Declared but unwired SIO, CTC, second ACIA, LED, and CompactFlash ports on other profiles are not supported hardware. Bare parameterless connection methods and direct key-event methods in the connection interface are unimplemented; interaction goes through byte-based terminal input/output.
- Preserve existing settings keys and JSON fields when interoperability with saved installations is needed. In a fresh implementation, the storage format and UI technology may differ as long as equivalent user-visible state survives restarts. The
user.configkey/value format is the current storage format, not a language requirement. - Verify a reimplementation against the examples and the matrix below, using an isolated settings store, temporary program/CF files and a loopback or fake serial device. Do not require physical RCBus hardware. The published Zilog Z80 CPU User Manual (UM0080) and ECMA-48 control-sequence specification can be used for instruction and terminal semantics beyond the explicitly enumerated acceptance subset; neither requires access to this source repository.
| ID | Setup and stimulus | Observable expected result |
|---|---|---|
| UI-01 | Fresh settings; start, open Serial, open Settings, return to Serial, select Serial again | First screen has no page content; Serial then Settings then Serial are exclusive; last selection collapses the serial panel without disconnecting or discarding its terminal. |
| UI-02 | Resize Serial panel to 420, Emulator panel to 300, restart | The two widths remain independent, 420 and 300; without stored widths each is 360. |
| UI-03 | Choose Dark; select SCM-S2, a program path and input switches 8 and 1; restart |
Dark theme, profile, path basename/full path and input byte 81 (saved decimal 129) return. Settings Reset then restart removes those selections and requests system theme, but leaves selected files on disk. |
| SER-01 | No port, then a port with no configuration; press Power in each case | Both remain disconnected; the port list can be refreshed by opening its selector. |
| SER-02 | Configure a test serial port to 9600, 8 data bits, no parity, one stop bit, no handshake; connect; inject 41 42 |
Port opens with RTS/DTR set; AB appears on terminal; framing selectors cannot be changed until disconnected; disconnect clears the terminal. |
| SER-03 | Send 41 0D 42 with character delay 2 ms and line delay 7 ms |
Port receives bytes in exactly that order; delay after 0D is 7 ms, and after each other byte 2 ms. With both delays zero, one bulk write is used. This tests the requested pacing policy, not exact OS scheduler latency. |
| TERM-01 | Split 1B 5B 32 4A across two receive chunks, then send 41; send 1B 5B 32 3B 33 48 42 |
Parser waits for the split clear-screen sequence, then displays A after clearing; B appears at row 2, column 3. |
| TERM-02 | Send 1B 5B 3F 31 68; press Up; send 1B 5B 3F 31 6C; press Up |
Connection receives 1B 4F 41, then 1B 5B 41. |
| TERM-03 | Select text with pointer without mouse tracking; right-click with clipboard containing A and U+00E9 |
Selection copies screen text; paste sends 41 C3 A9 in order. |
| CPU-01 | Load bytes 3E 41 32 00 80 F3 76 at bank 0 address 0000; run |
Z80 executes LD A,41, LD (8000),A, DI, HALT; shared RAM at physical 0xF8000 becomes 41. With the default stop-on-DI+HALT behavior execution completes and the power indicator turns off. |
| MEM-01 | Start empty, write 5A to CPU 0000, write 03 to port 78, write A5 to CPU 0000, write 66 to CPU 8000; switch back to bank 0 |
Bank 0 0000 reads 5A; bank 1 0000 reads A5; either bank's 8000 reads 66. Selecting bank 31 and reading 0000 also returns 66 because of the physical alias. |
| LOAD-01 | Load each no-file, empty, 32,769-byte, exactly-1-MiB, 1-MiB-plus-one, HEX and missing-file fixture from the table above | Assert each specified memory byte, message, loaded byte count, bank-zero restoration, and whether CPU start occurs. |
| F1-01 | Select SCM-F1; read unmapped port A1; write control 80 at A2, receive 41, read A3, write 55 to A3; write output byte A5 at A0 |
Unmapped read FF; ACIA status/queue follows table above and terminal receives byte 55; DIO output LEDs 8, 6, 3, 1 turn on. No IDE or ACIA CPU interrupt source is installed. |
| F2-01 | Repeat F1-01 on SCM-F2 |
Same port map and behavior; SCM-F2 remains a separately selectable profile. |
| S2-01 | Select SCM-S2; use ACIA 80/81 and DIO 00 |
ACIA byte queue, DIO input/output and FF on an unmapped port behave as above; no IDE or ACIA CPU interrupt source. |
| S3-01 | Repeat S2-01 on SCM-S3 |
Same wired ports and behavior; separate profile and persisted input/file settings. |
| S7-01 | Select SCM-S7; use ACIA 80/81 and DIO 00; inspect interrupt after enabled ACIA receive |
Same byte I/O as S2 plus an asserted Z80 ACIA interrupt source; IDE responds only on 10-17. |
| S7-02 | In S7, read IDE status, select drive 1 then drive 0, write EC to command port and read 512 data bytes |
Observe 50, then FF for unselected drive, then 58 after IDENTIFY; data block and final 50 match the identity contract above. No CF sector transfer occurs. |
| S8-01 | Repeat S2-01 on SCM-S8; probe IDE status 17 |
S2-style ACIA/DIO; unmapped 17 returns FF, and selecting a CF path does not add IDE. |
| PKG-01 | On macOS, build once for osx-x64 and once for osx-arm64 |
Each DMG name contains version 0.1.0 and its own runtime identifier; each contains Retroworks RCBus.app and an Applications shortcut. The app bundle declares minimum macOS 10.15 and executable Retroworks.RCBus. Running the app, device access, signing, and the crash window require separate on-device verification. |
Application failures are observable but do not imply recovery semantics that are not implemented: a serial-port open exception is not handled inside the serial page; an emulator worker fault is reported as Error: ... on its terminal and turns off its indicator. Manually stopping an emulator requests cancellation; its task may then report Execution Completed as it exits. A serial port's Closed event is not raised by this implementation, so automatic serial-disconnect indication must not be assumed.
These fixtures define a self-contained, testable core, not a proof of pixel-identical UI or complete XTerm/Z80/ATA compatibility. Additional escape sequences, undocumented Z80 behavior, full ATA sector commands, platform serial-driver behavior, precise visual assets and all failure races are not specified by the existing program's requirements. Do not silently treat them as covered by a passing matrix.