0

Color Without Color: Apple II Computer Graphics #Apple #Hacking #Video #AppleII

Color Without Color: Apple II Computer Graphics

A great write-up by paleotronic on how Steve Wozniak was able to get color from monochrome for the Apple II computer:

Released in 1977, the Apple II was one of the first personal computers marketed towards households rather than businesses. It was a complete computer – it had a keyboard for data entry and the ability to connect to a CRT monitor or a television set. However, unlike its competitors, the TRS-80 Model I and the Commodore PET 2001, the Apple II was able to display colour – but remarkably, it accomplished this without a dedicated colour video chip. The Apple II’s video hardware is actually monochrome!

So how does it display colours? The Apple II’s designer, Apple co-founder and chief engineer Steve Wozniak, discovered that if he repeated portions of the outgoing digital luminance signal (black or white) and injected it into the “colorburst” or NTSC colour signal, various patterns of pixels produced lines of different colours.

The “native” monochrome resolution of the Apple II is 280 pixels wide by 192 pixels deep. Each pixel is either on (1) or off (0). Steve found that using blocks of two pixels, he would get black (00), purple (01), green (10) and white (11). By shifting the timing of the colour signal, Steve was able to get an additional two colours, blue (01) and orange (10). This left him with a “high resolution” graphics mode (HGR) of 140×192.

Read more in the article. Subscribe to paleotronic.


Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Join 8,500+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – Python on Microcontrollers is here!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more https://www.instagram.com/adafruit/


Maker Business — Rethink Robotics closes shop. Long live collaborative robots #makerbusiness

Wearables — Cleaning is key

Electronics — Serial overkill

Biohacking — Biohacking Resources – Books, Talks and Podcasts

Python for Microcontrollers — CircuitPython @ Hackaday SuperCon #ICYMI @circuitpython @micropython @ThePSF #Python

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



No Comments

No comments yet.

Sorry, the comment form is closed at this time.