Videopac Programming

(sorry for the bad layout, but this page is for a functional purpose only, not to represent anything ... if you don't like it, don't use it)

here's some info for programming the Videopac/Odyssey2 - you can find some roms and sourcecode developed by yours truly, technical info and links to some useful sites:

Unofficial O2EM Port

Here's a page for my unofficial O2EM Port - my own version of O2EM with some new features (better debugger for developers, supports 2 real PC-Joysticks and more)
This page also contains all info needed to compile o2em for yourself on a windows platform.

Links to other sites (take a look at those first before trying to use anything on this site):

Videopac Programming page of Soeren Gust - downloading (and reading!) his pdf is a very good starting point ...
Rene G7400's Site (lots of hardware info to be found here)
videopac.nl Forum - were the videopac/Odyssey2 collectors/players/programmers meet

some tools i developed while writing on a game to be released 2009:

(Legend for Controls: u = up, d = down, l = left, r = right, b = button, e.g. u / d +b means up or down with button pressed)


g7400src.txt - a documented G7400 ROM-Source - contains just the parts different from the original g7000src.txt found on Rene's site


Spritebuilder - sp_build.rom - Source


a little utility for use on O2EM or a real videopac machine to test combinations of 2 characters and build new sprites (like the ones used in e.g. "Killer Bees" ... or the guy with the funny hat in the screenshot)

Controls:

Stick

Movement

Action

0

u / d / l / r

Move character 1

0

u / d + b

Scroll up/down in character map for character 1

0

l / r +b

Change color (+/-) of character 1

1

u / d / l / r

Move character 2

1

u / d + b

Scroll up/down in character map for character 2

1

l / r +b

Change color (+/-) of character 2

 

WARNING:there is no code to check for character overlap, so using this on the emu produces different results on overlapping chars than using it on the real machine - I left it out because I wanted to try to find possible effects of overlapping characters ... nothing useful yet


Soundfindersndtest.rom - Source


lets you control the sound registers of the Videopac and find out, what the values mean and which sounds are produced with different settings of the control register. Shows the contents of the three data bytes and the control byte.

Controls:

Stick

Movement

Action

0

u / d

Byte 1 + / -

0

l / r

Byte 2 + / -

0

u / d + b

Byte 3 + / -

0

l / r + b

Sound off / Sound on

1

u / d

Noise off / Noise on

1

l / r

Shift = 0 / Shift = 1

1

l / r + b

Play Once / Loop Sound

1

u / d + b

Volume + / -


GridEditgridedit.rom - Source


Lets you paint a Grid using your joystick and manipulate the Grid-Registers (Dots, Fill, Color). This grid can then be used by just saving the registers in O2EM and include them in your programs.

Controls:

Type

Movement/Key

Action

Stick 0

u / d / l / r + b

move pointer and set/clear gridline on the way

Stick 0

u / d / l / r

move pointer

Keyboard

F

paint all grid lines (Full Grid)

Keyboard

C

delete all grid lines (Clear Grid)

Keyboard

1

Grid Dots on/off

Keyboard

2

Fill Mode on/off

Keyboard

3

next Grid color

Keyboard

4

next BackGround color

Keyboard

5

Luminance on/off