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Space Invaders Test Rom: Documented and Modified

Space Invaders Test Rom

I have a Space Encounters PCB with Ram errors I've been fixing and thought it would be nice if the Space Invaders Test Rom available on the web would work for Space Encounters as well. After burning one and trying it out, I found out it kind of does (at least for the ram tests). The main problem is that Space Encounters has a hardware special effect that allows the screen to fade up to an all white screen. When the machine is powered up this is on by default and must be turned off by the program. Since Space Invaders doesn't have the feature it doesn't account for it and the text on the Space Invaders Test Rom is unreadable because of the white screen.

While looking at the code of the Space Invaders Rom in order to fix this problem, I decided I'd learn quite a bit about the hardware / software interaction of the 8080 pcbs by documenting its code.

In order to create the Space Encounters Test Rom, I had to convert the Space Invaders Test Rom for use in TASM, the assembler I use for development. In the process, I cleaned things up a bit and it now can be assembled into an exact copy of the original rom.

So here it is: Space Invaders Test Rom Documented and ready for the TASM assembler

To assemble this file:

  1. Download and decompress TASM.
  2. Save the file in the TASM directory changing the .txt extension to a .asm extension.
  3. Type on the command line: tasm -85 -b -f00 si_test.asm
  4. The resulting .obj file can now be renamed for use in mame.
  5. The .obj can be burnt to a 2716 eprom or (if your board's strapping requires it) doubled and burnt to a 2732 eprom.

In case anyone is interested in my (now outdated) first pass at this (it includes the op codes and memory addresses):
Here it is: Original Space Invaders Test Rom Documented

Here is the zip containing the original binaries ready for burning to eproms:
Space Invaders Test Rom

The Space Encounters test rom is now completed and can be found here.


Modified Space Invaders Test Rom

Modified Space Invaders Test Rom

Frederic Rodo & Fabrice Girardot have modified the Space Invaders Test ROM adding many new features. They have given me permission to distribute these updates and they can be downloaded below. Thanks Frederic & Fabrice!

Note: To emulate the rom in mame rename the file test.h to invaders.h.

 

ROM
Version

Date

Download

Author

Notes

Preversion

Unknown, Documented
11/16/2007

Source

Binaries

Timothy SHIELS

arcade@
outerworldmedia.com

  • Test RAMS, INPORT, SOUNDS & WATCHDOG

V1.0

10/12/2013

Source

Binaries

Frederic RODO

fred@rodo.fr

  • Compute CRC32 check of all the roms
  • Add cross-hatch pattern for adjusting the screen
  • Add test for the game's shifters
  • Proper text display for the SI's portrait monitor orientation

V1.1

9/17/2017

Source

Binaries

Fabrice GIRARDOT

f4brice@gmail.com

  • Fix a small cosmetic bug on bad ram display
  • Refactor makefile
  • Add binaries in zip file for easy compiling on Linux
  • Add .png file for bad RAM identification
  • For those able to read French, there is a discussion about the bad ram display bug here.

V1.2

10/14/2017

Source
&
Binaries

Frederic RODO

spectroman or frodo13 on forum

fred@rodo.fr

  • Modify the test RAM to display all rams in error at one time.
  • Correct a display bug on INPORT test
  • Simplify the shifter matrix
  • Add manual