Getting started

Install the core first: Chapter 5 of the official MEGA65 User's Guide explains how to flash a .cor file into a core slot using MEGAFLASH. Use an available slot for the Nascom 2 core and do not overwrite the factory core in slot 0.

Start an alternate core: Switch the MEGA65 off, hold down NO SCROLL, then switch it on again. When the core selection menu appears, release the key and press the number of the slot containing the Nascom 2 core. Press the slot number without CTRL—holding CTRL while pressing a slot number opens the editor used to flash that slot instead.

NAS-SYS 3 appears after startup. The machine is ready to use immediately; the MEGA65 keyboard is all you need for your first experiments.

Displaying and changing memory

First, display memory starting at address $1000:

T1000

Then enter modify mode and write a few bytes:

M1000
23
42
FF
.

Use T1000 to check the result. The full stop ends input.

Loading a program from SD card

1. Put the NAS or CAS file in the /NASCOM2 directory on the SD card.
2. Press F11 to open the file browser.
3. Select the file with the cursor keys and confirm with Enter.
4. Note the displayed start address.
5. Close the browser by pressing F11 again.
6. Start the program, for example with E1000.

Starting Microsoft BASIC

After a reset, start BASIC from the NAS-SYS monitor with:

J

In the default configuration, simply press Enter when asked for the memory size. To return to NAS-SYS from BASIC, enter:

MONITOR

Important function keys

• F1 displays the complete keyboard mapping.
• F3 lists the NAS-SYS commands.
• F5 opens the hardware monitor.
• F7 opens the hardware diagnostics for the FDD and keyboard.
• F9 opens the save dialog.
• F11 opens the file browser for loading and mounting files.
• F13 opens the configuration screen.

In the hardware monitor, you can inspect registers and memory, modify RAM, and single-step through Z80 instructions with the space bar.