The Emulator window includes a menu bar above the simulated display. This page describes the options available from the menu bar.

All options are also available on the pop-up menu (right-click on the LED display area or keyboard background), so you may prefer to remove the menu bar using the appropriate View option.

The menu bar has four sub-menus: File, Action, View, and Help.

File

The File menu lets you copy bytes between the 6502 memory map and files:

Save As

This selection prompts you for the addresses of a range of bytes which are to be saved to file (the addresses must be four hexadecimal digits each, with the first no larger than the second). Once a valid range has been selected, click OK to choose the folder and name of the file to be written.

Only those bytes in defined ROM or RAM (including RAM on a RAM I/O chip) are saved. The bytes are saved in Intel Hexadecimal Object Fileformat, using only data and EOF records.

Load

Selecting this option lets you choose a file containing bytes to be loaded into the emulator. Bytes may be loaded into any defined RAM or ROM. The file must be in Intel Hexadecimal Object File format, using only data and EOF records. (Use Save As to create a sample file.)

Tape Record

This option (available only if the processor is running) starts recording on the simulated cassette tape recorder. It prompts for the name of the MIDI file to record to; once a valid name is given the recorder is started (indicated by a red ‘lamp’ at the top left of the display). The recorder waits for data initiated by the Acorn Monitor Store command, then records it. The recorder stops automatically when no new data has been written for one second.

Tape Play

This option (available only if the processor is running) starts the simulated cassette tape recorder playback. It prompts for the name of the MIDI file to play back; once a valid name is given playback starts immediately (indicated by a green ‘lamp’ at the top left of the display). Be sure to initiate the Acorn Monitor Load command before starting playback. The recorder stops automatically shortly after the recorded track ends.

Tape Stop

This option stops the tape recorder if it is recording or playing back.

Tape Mute

When checked, this mutes the audio feedback normally provided while recording or playing a tape (MIDI file).

Exit

Halts the emulator and ends the program.

Action

The Action menu lets you control the emulated 6502 processor:

Halt

Halts the processor (if running, otherwise this option is greyed). When halted, the state of the 6502's registers and memory can be inspected with the mini-debugger.
You can also toggle the processor between Halt and Run by using the PC's Pause key.

Step

Runs the processor for one instruction (if halted, otherwise this option is greyed).
You can also step the processor (if halted) using the PC's Space bar.

Run

Runs the processor until halted (if already halted, otherwise this option is greyed). When running, the data in the 6502's memory map can usually be inspected with the Acorn Monitor.
You can also toggle the processor between Halt and Run by using the PC's Pause key.

Reset

Resets the processor and starts it running (the same as clicking on the rst button on the Acorn keyboard).
You can also reset and start the processor at any time by pressing the PC's Esc (Escape) key.

IRQ

Initiates a simulated maskable Interrupt Request (IRQ). This will remain pending until either the emulated program turns off the I mask flag (in the 6502 P register) or the processor is reset.

NMI

Initiates a simulated Non-Maskable Interrupt (NMI). This takes effect immediately the next instruction is run.

Power off/on

Simulates turning the power supply to the computer off and then back on. After this sequence, the ROM is loaded with the monitor, RAM has random values, the RAM-I/O outputs are all high, and the processor is halted.

View

The View menu lets you alter the appearance of the emulator. Click on an option to toggle it between checked and unchecked state:

Menu

If checked, the menu bar is displayed. If unchecked it is omitted from the window. In either case all options are available on the pop-up menu (to show this, right-click on the Acorn display or keyboard background).

Keyboard

If checked, the keyboard area and buttons of the simulated Acorn keyboard are displayed. If unchecked they are omitted. In either case the function of the keyboard is available by using the corresponding PC keyboard keys (or Esc for Reset).

Debug

If checked, the mini-debugger display is shown at the bottom of the window. If unchecked it is omitted. When the processor is halted, the mini-debugger lets you inspect the state of the 6502 processor, view and modify memory, single-step, set the Program Counter and run, and set ‘hard’ breakpoints.

The simulated Acorn LED display is always displayed.

Help

The Help menu provides access to additional information. The first two options require a working Internet connection:

Website

Opens your default web browser at the Acorn System 1 Web Site. (http://www.cary.demon.co.uk/acorn)

Emulator pages

Opens your default web browser at the Emulator pages at the Acorn System 1 Web site. (http://www.cary.demon.co.uk/acorn/acornEmulator.html)

About

Displays a conventional ‘About’ panel, showing the version and date of the Emulator. This panel also gives push-button access to the Web pages, and can be displayed by pressing the PC's F1 key.