AMIGA 500 for MEGA65 Version 1 is released

Experience the AMIGA 500 with great accuracy and sublime compatibility on your MEGA65! It runs nearly all games and demos and it offers convenient features.

• Amiga 500, OCS chipset, PAL
  
• Cycle accurate 68000 CPU
  
• Kickstart 1.3
  
• 512 KB Chip RAM plus 512 KB Slow RAM (trapdoor expansion), 1 MB in total
  
• One floppy drive (df0:): read/write standard 880 KB *.adf disk images
  
• Real Amiga mouse in port 1, joystick in port 2
  
• MEGA65 keyboard mapped to the Amiga keyboard and raw Amiga keyboard mode
  
• Interlace ("laced") modes with a built-in flicker fixer on HDMI
  
• Analog output in parallel to HDMI: scandoubled 31 kHz VGA or raw 15 kHz RGB for CRTs (SCART), selectable in the menu
  
• Adjustable picture, per Amiga screen mode: HDMI crop plus analog position (pan) and analog overscan, via a config file and helper tool
  
• Battery-backed real-time clock

As this is a "Version 1" there are many large and small features missing. Here are some of the larger features that are not there yet:

• Kickstart ROM size limited to 256kB, so no Kickstart newer than 1.3.x
  
• Only one floppy drive (df0:)
  
• No hard disk support
  
• OCS and PAL only: no ECS, no AGA, no NTSC, no Fast RAM

LEARN MORE AND READ THE DOCS: https://a500.mega65.org/

Download from the MEGA65 filehost: https://files.mega65.org?id=bdbf637c-83b5-45c4-802f-0fd459f6b49e

Apple IIe Core – Very Early Work in Progress

Here is a very early WIP release of the Apple IIe core for the MEGA65 (R3 and R6).

At the moment, the core only supports .nib disk images but with stability issues. .nib files are readily available online.

You can use the following tools to convert dsk to nib if you're unable to find a nib image to test
Source code is provided here but must be compiled under gcc ( use gcc -o dsk2nib.o dsk2nib.c ), should work under Linux or cygwin.
https://github.com/slotek/dsk2nib

Current Status
Supports .nib floppy disk images.
Drive A only.
Keyboard is functional, but the MEGA65's key glyphs are not yet fully mapped to the Apple II layout.

What's Missing

The following features are not yet implemented:

• HDD support
  
• Mockingboard support
  
• Joystick support
  
• Serial support
  
• Drive B

This is still a very early work in progress and the floppy subsystem is not yet reliable.

Current issues include:

• Disk read may fail after mounting a disk.
  
• The machine may occasionally crash while a disk is loading.
  
• Writing to disk is likely not working, this hasn't yet been tested.
  
• Disk swapping does not currently work correctly. For example, Where in the World Is Carmen Sandiego? does not recognise the second side when prompted to swap disks. This may be an emulation issue or simply a bad disk image, I haven't confirmed which yet.

I currently believe these problems are related to timing differences as floppy implementation is timing sensitive, this needs investigation and testing to confirm.

Disk Formats

At present, only .nib images have been tested successfully.

The original MiSTer core appears to boot from several formats (such as .nib, .dsk, po), so I suspect it performs some form of image conversion or pre-processing before presenting the data to the Apple II core. I haven't investigated that pipeline yet, but it's something I'd like to bring across to the MEGA65 in the future if possible.

Next Priorities

My immediate priority is making floppy loading 100% reliable.

Once the disk subsystem is stable, I'll move on to:

• Complete keyboard mapping with the option to switch via the OSD.
  
• Drive B support.
  
• Joystick support / Mouse
  
• HDD support.
  
• Mockingboard
  
• Super Serial ?

Please keep in mind that this is an early preview, intended mainly for testing and feedback rather than regular use. If you do try it, I'd love to hear what works and what doesn't.