Arkanoid Controller 9-bit result test ROM

Discuss emulation of the Nintendo Entertainment System and Famicom.

Moderator: Moderators

Post Reply
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Arkanoid Controller 9-bit result test ROM

Post by lidnariq »

Fiskbit and I have been discussing the Arkanoid ("Vaus") controller and after rewriting the page on the wiki about how it works, figured that we should have a test ROM to demonstrate how to get a 9-bit result from it.

The short of it is: Load the 9 bits of result before you strobe it.

Source is included, public domain. Handles two controllers in a Famicom expansion port, or just the one in the player 2 NES port.

Emulator pass is: you get a 9-bit result (the LSbit changes). Emulator "good enough" is: you get an 8-bit result (result always even or odd).
Attachments
vaus.zip
(5.64 KiB) Downloaded 114 times
kmg
Posts: 63
Joined: Tue Dec 07, 2021 10:12 pm

Re: Arkanoid Controller 9-bit result test ROM

Post by kmg »

In practice what are the ranges of readback on physical controllers with this test?
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: Arkanoid Controller 9-bit result test ROM

Post by lidnariq »

Fiskbit's two controllers had ranges of 88-1D0 and 91-1D4.
Fiskbit
Posts: 891
Joined: Sat Nov 18, 2017 9:15 pm

Re: Arkanoid Controller 9-bit result test ROM

Post by Fiskbit »

The 88-1D0 controller is an Arkanoid II controller (which I've never adjusted) and the 91-1D4 an Arkanoid I controller with no centering pot. I'll need to play with the scaling pot at some point to see what range sizes are permitted (and how detectable this is in software). A larger range than $A0 steps would benefit Arkanoid II.
kmg
Posts: 63
Joined: Tue Dec 07, 2021 10:12 pm

Re: Arkanoid Controller 9-bit result test ROM

Post by kmg »

Thank you both for the research, test rom and info. Looking forward to the scaling pot results. Shouldn't that range expression be double now given we're no longer ignoring the extra bit? It's roughly $140 steps.
Fiskbit
Posts: 891
Joined: Sat Nov 18, 2017 9:15 pm

Re: Arkanoid Controller 9-bit result test ROM

Post by Fiskbit »

You're right. I've updated the article to make this clear and note whether numbers are referring to an 8-bit or 9-bit read.
Post Reply