You can supply other A800 XL OS ROM as games/ATARI800/boot.rom. Alternative Basic ROM can be placed to games/ATARI800/boot1.rom. Alternative A800 OS-A ROM as games/ATARI800/boot2.rom. Alternative A800 OS-B ROM as games/ATARI800/boot3.rom.

Integrated OS ROMs include SIO turbo patch (fast disk loading). Note that the single fact that this patch is present can break some titles, especially the timing sensitive ATX disk based ones.

Turbo ROM has hot keys to control the turbo mode:

SHIFT+CONTROL+N Disable highspeed SIO (normal speed)
SHIFT+CONTROL+H Enable highspeed SIO

Another alternative is to load and set the ROM files from the OSD menu, they will become permanent (use Backspace when loading to clear them), but only if there are no alternative boot.rom files, otherwise those will take precedence. Yet, there is an option to change that behaviour too (that is, keep the boot.rom files on the SD card, but have the ROM data loaded from the OSD selected files on core initialisation).

Additionally, you can control the speed of turbo loading in OSD menu.

Disks

A800: After mounting the disk, press F10 to boot. Some games don't like the Basic ROM. Keep F8(Option) pressed while pressing F10 to skip the Basic. You can also boot a disk directly from the D1: drive using the first menu entry, the F10 Reset and F8 Option keys are applied automatically, any mounted carts are unmounted. For ATX disk titles that are timing sensitive, you may also want to try to change the emulated drive timing between the older 810 disk drive, and the XL line 1050 one (this does not apply at all to non-ATX titles, the option has no effect). Moreover, some ATX titles will only load on the PAL or NTSC machine only, depending on which system they were designed for.

Executable files

A800: There is an entry to directly load the Atari OS executable files (the so called XEX files) using a high-speed direct memory access loader. If a title does not load, you may want to try to switch the loader location in Atari memory (Standard - it sits at 0x700, Stack - it is located at the bottom of the stack area at 0x100).

Classic Atari 800 mode

When selecting OS-B in the Machine/BIOS menu option, the core works in the classic Atari 800 mode (reset required to take effect), and different memory layouts are available / activated. Note that the 52KB memory layout is not compatible with the core built-in 800 OS-A/B system, it freezes the boot process. This is not a core bug, but an Atari 800 legacy. To remedy this you have to use / load the genuine OS-A/B rom file.

Cartridges

With the newer version of the core the database of supported cartridge types have been extended and the ability to "stack" cartridges have been added. The stacking is only working or is useful when the first cartridge is a pass-thru type, these are the different kinds of Sparta DOS X cartridges. Moreover, now the selected distributions of SDX provided by the Sparta DOS X project are supported, you can use the rom files for Ultimate 1MB or Super Cart directly with the core. When stacking the size of both cartridges is limited to 1MB (this is only partly checked) when normally cartridges up to 2MB in size are supported. This, however, is not an actual limitation as all SDX releases are under 1MB and so are any useful to stack programming language cartridges, like MAC/65 or Action!. In the classic 800 mode, see above, the stacked cartridge slot doubles as the right cartridge slot of Atari 800 and the actual stacking for SDX is not supported.

Differences from original version

Joystick/Paddle mode switched by joystick. Press Paddle1/2 to switch to paddle mode (analog X/Y). Press Fire to switch to joystick mode (digital X/Y).
Use ` key as a Brake on reduced keyboards.
Cursor keys are mapped to Atari cursor keys.
PAL/NTSC mode switch in settings menu (A800)
Video aspect ratio switch in settings menu
Switchable side clipping of the video output to hide the GTIA "garbage".
An option to turn off the hi-res Antic extension from the original core, which brakes some titles.
Some optimizations and tweaks in file selector and settings menu navigation.
Standard OSD menu for cartridge/disk selection.
Mouse emulates analog joystick(Atari 5200) and paddles(Atari 800).
Fire 2 and Fire 3 on joystick.

Disable Basic ROM by Joystick.

Fire 2 on joystick acts as an OPTION key while reboot. It's valid only 2 seconds after reboot. After that Fire 2 doesn't affect the OPTION key.

More info

See more info in original instructions and original manual.

Download precompiled binaries

Go to releases folder.

Languages

VHDL 63.3%

Verilog 22.2%

SystemVerilog 12.4%

Tcl 1.6%

Assembly 0.4%