I thought this was caused by #11, but apparently not.

Replaces the on-board RAM (?) and adds

• 8K of RAM
• 1K/2K EPROM (one chip, 2708 or 2716), replaces RAM
• 2 PIAs

• RAM
  • 1K (0000–03FF)
  • 2K (0000–07FF)
  • 4K (0000–0FFF)
• EPROM
  • Dreamsoft 1 (1800–1FFF), PROM 0 on Dreamsoft/EA Expansion Board
  • CHIPOS (C000–C3FF)
  • Dreamsoft 2 (C000-C7FF)
• ASCII keyboard?

Check out https://love2d.org/forums/viewtopic.php?f=4&t=88636

Instead of a WAV file: https://love2d.org/forums/viewtopic.php?f=4&t=88260

https://johnearnest.github.io/chip8Archive/?sort=platform

Some of the aliens experience graphical glitches.

Fall back to just display and keyboard input

https://github.com/tobiasvl/chiposlo/raw/master/chipos_manual.pdf

After loading Dream Invaders from $0200 to $06FF, and then loading the following checksum program from the Dream Invaders manual afterwards:

    CPU.memory[0x700] = 0xCE
    CPU.memory[0x701] = 0x02
    CPU.memory[0x702] = 0x00
    CPU.memory[0x703] = 0x4F
    CPU.memory[0x704] = 0xE6
    CPU.memory[0x705] = 0x00
    CPU.memory[0x706] = 0x1B
    CPU.memory[0x707] = 0x08
    CPU.memory[0x708] = 0x8C
    CPU.memory[0x709] = 0x07
    CPU.memory[0x70A] = 0x00
    CPU.memory[0x70B] = 0x26
    CPU.memory[0x70C] = 0xF7
    CPU.memory[0x70D] = 0x97
    CPU.memory[0x70E] = 0xFF
    CPU.memory[0x70F] = 0x7E
    CPU.memory[0x710] = 0xC3
    CPU.memory[0x711] = 0x60

The checksum at location $00FF will sometimes be $AA (the correct sum) and sometimes $83.

• LÖVE fullscreen mode
• All windows are hidden except Display
• Display window is scaled up to fill the screen

Right now, the main loop runs the CPU at 1 MHz, and draws to the screen at 50 Hz.

Instead, the VDG should be emulated. It should request an interrupt from the CPU and then draw the screen (using DMA).

The TIME and TONE variables in CHIPOS are not properly decremented in some cases. When?

This is the cause of several current bugs:

• Dream Invaders freezes when either an invader or the player is hit
• Mini Lights Out only inverts the title screen once

• Remember setting in INI file
• If setting is on, init RAM with random. Otherwise, init with 0.
• When turning setting on and off, change RAM values of uninitialized RAM, but not the initialization flag

Make a debug object that can access all components.

One special case for the address bus: It should not acknowledge the PIA's IRQ when reading off the PIA's data pins.

Probably best to use an INI file since that's what imgui uses...

The release apparently has a bug: It crashes when attempting to load Dream Invaders.

Not sure why, since it works on master.

Current mapping assumes QWERTY

There's way too little separation between parts right now. memory shouldn't belong to the cpu, and I need somewhere to store stuff like the number of cycles (right now it's a global…).

• Left = 0
• Right = 1
• Fire (space?) = 3

The EPROM should be mirrored all the way up to $FFFF (which is the actual location of the interrupt vectors).

Consider using a CRT fade out effect to mitigate flicker

• C000 - C3FF: CHIPOS, CHIPOSLO or DREAMSOFT 2
• 1800 - 1FFF: DREAMSOFT 1

Dreamer issue 3

Uses PIA B (extended IO)

Use LÖVE console?

Uses PIA B (extended IO)

Dreamsoft 1

While playing Dream Invaders, sometimes an alien on the front row will suddenly die (without being shot) and be vertically displaced, and the game is lost (presumably because the game thinks the alien managed to reach the bottom of the screen).

PIA A at $8020

http://www.mjbauer.biz/Dream6800-sound-fx-mod.pdf