Displaying Bitmaps On The Apple II

October 5, 2018 by Lewin Day 34 Comments

The Apple II was the popular darling that truly kicked off the ascention of the company that would later bring you darlings such as the iMac, iPod, and iPhone. The brainchild of the legendary Steve Wozniak, it was a low-cost home computer that made use of some interesting compromises to create video output with the bare minimum components. This can make it difficult if you want to output full-bitmap graphics on the Apple II – but it is certainly possible.

[cybernesto] set about completing this task, and released VBMP on GitHub. Programmed in assembly, it builds upon the work of democoder Arnaud Cocquière to display bitmap images on the vintage 6502-powered machine. Capable of displaying monochrome images in 560 x 192 or sixteen colors in 140 x 192, it loads slowly but does get the job done.

We’ve seen similar development underway elsewhere, too – on this vintage satellite tracker project. [Keplermatic] reports that their code runs at a similar speed to the VBMP loader, despite doing several things differently. It’s also available over at GitHub, for your reading pleasure.

If you’re looking to achieve something similar with your vintage hardware, it’s worth a look. Having the source available makes integrating it into further projects a snap. Learning to program these older machines can be challenging, but that’s half the fun – and when you build something awesome, be sure to drop it on the tips line.

A Simple And Inexpensive GPS Navigation Device

April 29, 2015 by Rick Osgood 18 Comments

There are plenty of GPS navigation units on the market today, but it’s always fun to build something yourself. That’s what [middelbeek] did with his $25 GPS device. He managed to find a few good deals on electronics components online, including and Arduino Uno, a GPS module, and a TFT display.

In order to get the map images on the device, [middelbeek] has to go through a manual process. First he has to download a GEOTIFF of the area he wants mapped. A GEOTIFF is a metadata standard that allows georeferencing information to be embedded into a TIFF image file. [middelbeek] then has to convert the GEOTIFF into an 8-bit BMP image file. The BMP images get stored on an SD card along with a .dat file that describes the boundaries of each BMP. The .dat file was also manually created.

The Arduino loads this data and displays the correct map onto the 320×240 TFT display. [middelbeek] explains on his github page that he is currently unable to display data from two map files at once, which can lead to problems when the position moves to the edge of the map. We suspect that with some more work and tuning this system could be improved and made easier to use, of course for under $25 you can’t expect too much.

Driving A T6963C Based Graphic LCD

April 23, 2012 by Mike Szczys 7 Comments

[Tom Fleet] spent the dreary weekend inside learning how to drive this T6963C based graphic LCD controller. Although this is his first time venturing away from HD44780 character displays, the availability of an Arduino library helped him go from being a newbie to coding his own animated graphics.

The hardware setup is straight-forward. The screen has a 20-pin connector and operates at 5V. We don’t see it on his protoboard, but usually these displays also need a potentiometer which serves as a voltage divider for the screen contrast. The data and control pins eat up most of the available I/O on the ATmega328 chip he used, but the I2C and SPI pins are still open and he plans a future project to make this a wireless display for his PC using one of those protocols.

As for fonts and animation, [Tom] links to several tools which will come in handy. There’s a font program that will convert Windows system fonts into a C file for use on the Arduino. The animations start with a 1:1 ratio animated graphic drawn with his favorite image editing software. He then converts those to monochrome bmp files and used bmp2c to convert each frame to a C array. After the break there’s a seven second example that would work well as a boot screen for his project.

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How To Generate Font And Picture Header Files

September 29, 2009 by Mike Szczys 19 Comments

custom_fonts_displayed

Displaying custom fonts or images on an LCD screen using a microcontroller usually requires quite a bit of work. We’ve used some readily available tools to make this a bit easier for your next project. Our python script will convert BMP files into a header file ready for use with AVR microcontrollers. We’ll walk you through it after the break. Continue reading “How To Generate Font And Picture Header Files” →