15. May 2008 by pilot.

Using the new double buffered graphic library (see previous post) we can now create simple animations. In chapter 12 we have already seen how to visualize a 2D function using a grid and a bit of perspective (isometric). The next obvious step is to look into 3D objects and how to animate them by moving and rotating them in space. Read the rest of this entry »

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10. May 2008 by pilot.

In the good old times, when studying at the University of Trieste, I particularly enjoyed Rational Mechanics, a required class for any EE Master back then, presented by professor Enzo Tonti. One of the things that were always making his lectures a pleasure (and a challenge) was his constant reference to, and practical use of, personal computers to illustrate visually the concept at hand.

Mind those were the early days of the Apple II, the Commodore C64, the Sinclair Spectrum and for the few lucky (and rich) ones among us the first IBM XT personal computers. The graphic capabilities of those personal computers were primitive to say the least. In fact, a single PIC24F128GA010 has today more program memory than any of those personal computers and the resolution of the video output, using the AV16 board we developed in the book (without any hardware assistance), is actually pretty close. Yet prof. Tonti used to teach us how to develop effective demos using little more than a few lines of BASIC or, I should say, of the “soup” of BASIC dialects that were popular at the time… (Actually prof. Tonti developed a brilliant scheme to identify a sort of minimum common denominator among all those disparate systems and Basic dialects that he called Inter-Basic if I recall correctly… there must be a web site somewhere where all this is documented)…

We simulated graphically the motion of planets around a sun, the complex motion of pendulums of various kinds, we animated objects in 2D and 3D! Key to all those graphic exercises was the ability to alternate fast images on the display to obtain the illusion of motion….

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Posted in Chapter 12, Tips and Tricks, AV16 | 1 Comment »

5. March 2008 by pilot.

PICTail(tm) Plus is the name that Microchip uses for the expansion socket offered by the Explorer16 boards. It is one of the easiest and most flexible options available for prototyping out there. All the signals from a 100 pin PIC microcontroller are grouped logically and conveniently in three sections so that if only a few signals are required a smaller board can be arranged. The edge of any PCB can be quickly transformed in an inexpensive (as in free) connector as soon as you realize that all it takes is a set of 1mm spaced traces (gold plating is an option you might consider for longevity). NOTE that all connections are clearly documented in the appendix of the Explorer16 User Guide (DS51589) .

The AV16 board that I developed to support the code examples of the book is only one example of PICTail Plus expansion board, on microchiDIRECT you will find many other options to support: IrDA, Graphic displays with touch sensing, Ethernet, SD Cards and more.

But my all times favorite is the simplest one of all: AC164126  also known as the:

Prototype PICTail Plus board 

For $20 you get 3 (three) boards actually. All the signals are accessible in a standard spacing four row line up with silk screen call outs. Get your soldering irons warm!

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13. January 2008 by pilot.

So this is what the AV16 board looks like (I just realized I did not have pictures of the completed board on the web site):

In this picture you see it mounted on the Explorer16 first slot. The audio jack on the right side is connected to my computer set of amplified loudspeakers (with a nice sub-woofer for extra humph) and the video jack on the left is connected to a TV.

To check the availability of the AV16 board and/or to order one, refer to the AV16 page on the FlyingPIC24.com web site.

In reality I use one of those cheap portable LCD DVD players ($99 last Christmas at Fry’s) as my output device during development and debugging.

If you look carefully at the bottom of the board you will notice that I have made some modifications to the video circuit (added one resistor and a “blue” wire) while experimenting with … new features … in particular I was trying to simplify further the graphic.c routines having the OC3 peripheral produce directly the SYNC signal. More on this soon…

If you really have good eyes though, you will notice that I was not using exactly a PIC24 when this picture was taken…

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