Local emulation workspace

JR-800 Emulator

Initializing worker
Canvas support is required to render the LCD matrix.
LCD appearance

Appearance settings are remembered in this browser.

LCD panel unavailable

The matrix composition and indicator RAM locations are provisional. Indicator RAM unavailable; battery telemetry omitted. Raw indicator values never imply a lit or unlit physical segment.

Keyboard unavailable

POWER

02

Target image

Choose a local ROM or use the remembered ROM, then start BASIC or a RAM program.

JR-800 hardware model

J8R / RAW

Load one owner-provided J8R container or 32 KiB raw ROM for addresses $8000-$FFFF.

No ROM remembered in this browser.

After a successful load, the ROM and BASIC startup options are remembered in this browser. On your next visit, press Start BASIC to load the remembered ROM.

Unsupported reads return $FF; writes are discarded. Applies when loading a ROM.

Sets local date, time, weekday and leap-year state once at BASIC startup (2000-2099). Uncheck to keep the original startup values. WAKE alarm and wake-up are unsupported.

Machine state

Save CPU, RAM and devices in this browser. Load the same ROM before restoring. RTC is kept separate and is not rolled back. Restore pauses the machine; press Resume to continue.

Save data to a file

Run SAVE or MSAVE in BASIC. When saving finishes, download the result as J8A or WAV. SAVE with the A option is also supported.

Start a supported BASIC ROM to capture saves.

    Up to 32 saves are kept in this session. Download them before loading another ROM or closing this page.

    BASIC and machine-code programs are detected automatically. BASIC loading requires a supported BASIC ROM at its command prompt.

    WAV files are converted locally. ROMs are remembered only in this browser; programs and working RAM last only for this session. These files are never uploaded.

    Explicit experimental configuration

    Disabled items remain unknown or disconnected. Enabling an item is an experiment input, not a hardware claim.

    Reset state
    RAM
    Display and calendar
    External inputs
    Developer debugger

    SDK

    SDK application debugging

    Load a synthetic SDK application and optional integrity-bound source data for developer debugging.

    Calendar ADJ is one software-qualified RP5C01 action. No physical input level or pulse is modeled.

    03

    Registers

    No target
    PC
    ----
    SP
    ----
    X
    ----
    A
    --
    B
    --
    CCR
    --
    State
    --
    Calendar ALARM
    --
    Port 2 timer out
    --
    LCD substituted reads
    --
    Ignored I/O accesses
    --

    Calendar ALARM is the internal RP5C01 pull-down request; Port 2 timer out is a CPU-internal logical state. Physical JR-800 wiring is unresolved. LCD substituted reads count software replacements under the explicit LCD experiment and do not validate physical decoding.

    Cycles0

    Expression watches

    ExpressionValue / errorAction
    No expression watches

    Symbol watches

    SymbolValue / metadataAction
    No symbol watches

    04

    Current instruction

    $----

    No application loaded

    No source mapping

    Raw keyboard response

    Keyboard activity unavailable

    05

    Memory

    No memory loaded

    06

    Instruction history

    #PCBytesACyclesFault
    No history

    07

    Architectural access trace

    0 records
    #InstructionKindAddressValuePrevious
    No accesses