vaporlock

ONE LINER: Vaporshow

Submitted by S.Elliott on April 25, 2026 - 3:16pm
Did you ever want to test whether there are any active bits at an unknown address or memory-mapped-IO port?  This one-liner uses vaporlock to distinguish active bits vs floating bits on the Apple data bus.
Tags: 
hardware
vaporlock
troubleshooting
one liner

ONE LINER: Jitterbox cursor

Submitted by S.Elliott on April 25, 2026 - 3:12pm
This precisely-timed machine code tricks a 2513 character generator into displaying a dancing-box at the current cursor position, despite the fact that the character generator contains only 64 character shapes -- none of which is a box-shape!
Tags: 
vaporlock
one liner

Transmitting a simple datagram via Video Vapor

Submitted by S.Elliott on April 4, 2023 - 5:36pm
Synopsis:
  • Define a short datagram to be transmitted via vapor from visible screen memory.
  • Encode single-cycle accurate video phase via vapor datagram.
  • Construct a routine to receive the vapor datagram and synchronize itself to the video scanner.
  • Write a simple BASIC program to demonstrate all that!
Tags: 
vaporlock
asm

Clumsy (but pretty!) attempts to map video scanner's memory access

Submitted by S.Elliott on March 28, 2023 - 10:30pm
Some experiments and variously messy results from trying to map how often the video scanner reads each byte of screen memory while creating each video frame.

Green indicates bytes that were detected only once per frame.

Purple indicates bytes that were detected twice per frame.

Orange indicates bytes that were detected thrice per frame.

Blue indicates bytes that were detected four times or more per frame.

Tags: 
vaporlock

Side-by-side graphics/text windows

Submitted by S.Elliott on December 6, 2022 - 3:10pm

This blogpost is a partial-transcript of a discussion from Apple2Infinitum on Slack, which was spawned from an even older Facebook thread.  Since it isn't easy to view the old discussions on Slack and Facebook, I've copy-pasted the messages, pictures, and code blocks below...

 

Scott Elliott Sep 3rd 11:29:17 AM

Tags: 
vaporlock
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