AIR orientation bug follow up

Small update:

If you have used the info supplied in my earlier articles here and here I am happy to announce that Adobe has fixed these issues in AIR3.4 and these hacks are no longer necessary.

In fact, if you want to use 32-bit colour in an Android AIR app, you need to ensure that you don't hack the Activity theme as this will result in forcing the app to 16-bit (something that had me scratching my head for a while!).

So thanks to Adobe for that, now if they can just fix the issues with URLLoader on 3.4+ and the ATF issues on nVidia based tablets then my life would get a lot easier...

If anyone from the Adobe AIR team reads this, please contact me! My team uses your product in ways you probably wouldn't believe and we are constantly pushing AIR to the limits of the technology. It would be awesome to partner with you on the issues we find.

-(e)

Implementing Artcfox's TLC5940 code on an Arduino, Part 3

Well its been a while... Real Life(tm) has been rather busy!
The code for this post has been gathering bit-rot on my drive so I thought it time to just put it up with a a short post (basically just a code dump) which I will follow up at a later point.

In the previous article we got the Arduino setup with appropriate clock fuse settings so that Matt's code would work. Based on this I took the sample code from CH9 and modified it to implement a small RGB pattern using some of the CH9 features, specifically the gamma correction.

CH9 is based around mulitplexing the output. I haven't used this as I don't have the transistors availabe to test it, so basically the output is still a direct drive of the attached LEDs with one colour per output pin on the TLC5940. However there is no reason that multiplexing shouldn't work. If you want to try it out, refer to Matt's original document and wire appropriately. If you apply the techniques discribed previously to the original CH9 code you should be good to go. You can use the attached code as a reference.

Hardware setup should be the same as per the first article. To see the correct visual output, wire each leg of an RGB LED to output pins 0,1,2 (R,G,B) then 3,4,5 etc. for a total of 4 LEDs. Then compile and upload the sketch and you should be good to go. The code will colour fade between each rainbow colour.

The code is available here. Go get it!

Next time I get a chance to get to the local electronics supplier I'll buy some of the appropriate transistors and wire up for the multiplexing capabilities of Matt's library and post up some wiring info and more code.

For questions etc, follow me:

or mail me at: sweetlilmre (at) gmail (dot) com

-(e)

Implementing Artcfox's TLC5940 code on an Arduino, Part 2

In my last post I detailed the basic hardware and software setup for getting Matt's TLC5940 chapter 3 code working on an Arduino. The the code doesn't do too much, but with the hardware and software working we can start to explore later chapters (where the interesting stuff happens).

At this point there is one more hardware obstacle to overcome. Matt makes use of an interesting feature of the Atmega328p called CKOUT. This is a chip level setting that can (according to the 328p datasheet) "output the system clock on the CLKO pin". Matt uses this to drive the TLC5940's GSCLK pin, a very clever way of handling the timing between the two chips.

Unfortunately the Arduino is not configured to support this by default and in order to switch on this feature, special configuration values in the 328p's flash known as "fuses" need to be be set. To do that, you need a chip level programmer.

The programmer I use is an USBtiny2 clone that I got off eBay for about 10 USD (search for "usbtiny" or "usbtinyasp" and you should get many results). Alternatively you can use a second Arduino to accomplish the same thing as per this link. Lastly, if you want to support a really fantastic company and get a great programmer with a nice case, please consider this one from Adafruit.
From this point on I will be assuming that you are using the USBtiny programmer, are on a Windows machine and are intending to program the fuses of an Arduino UNO.

At this point I am assuming that you have managed to install the drivers for your programmer. If you are using the USBtiny and are on Windows7 64-bit, this link may be helpful. If not, visit this excellent tutorial at Adafruit and get the drivers installed.


Once you have the hardware, you need to get hold of AVRDUDE. This is the software that will talk to your programmer and allow you to set the fuse bits. As of this article the latest AVRDUDE version is 5.1.1 and can be found here. If you are using an alternative programmer, please check compatibility with AVRDUDE at this page (look for the "-c programmer-id" reference).

Grab the windows archive (avrdude-5.11-Patch7610-win32.zip) and extract to a convenient location. I used "C:\temp\avrdude". Now you will need to connect your programmer to your Arduino.

Arduino ICSP port

Using the supplied 6 pin cable connect the programmer to the ICSP port on your Arduino, making sure you have:

• disconnected your Arduino from USB and any other circuitry.
• correctly identified the polarity and orientation of the programming cable and pin 1 on the ICSP port of the Arduino.

Once you have the cable correctly connected, connect the programmer to usb and the Arduino should power on.

Assuming everything is good to go: open a command prompt, change to the directory you extracted the AVRDUDE software into earlier ("c:\temp\avrdude" for me) and type:

avrdude -p m328p -c usbtiny 

See the advanced notes for additional information.

This command should print out something pretty much like this:

AVRDUDE basic output

If you get this result, add a "-v" to the command:

avrdude -p m328p -c usbtiny -v

which should spew out a whole load of text ending in something that looks like this:

Standard Arduino UNO fuse settings

What we want to do is to change the value of the lfuse from 0xFF to 0xBF to enable CKOUT.

To verify this, open this awesome AVR fuse calculator in another tab / window and check the lfuse checkbox that reads "Clock output on PORTB0; [CKOUT=0]". You should see the calculated value for lfuse change from 0xFF to 0xBF (and back when you uncheck the option).

Before we proceed any further, a word of caution:

Incorrect fuse settings can brick your Arduino!!!

If your fuse settings are not the same as the screenshot above you probably shouldn't proceed unless you are sure you know what you are doing.

Some clarification: You need to know that you have a good fuse read at this point. Your values may be different to mine but as long as they are good values you'll be okay.

Thanks to +Al McElmon who reported his hfuse value as D6 not DE. In the fuse calculator you can see that this is because EESAVE has been enabled. This could possibly be a setting on later Arduino Models?

Finally, if everything checks out and you are 100% sure of this, we are one command away from completion:

avrdude -p m328p -c usbtiny -U lfuse:w:0xBF:m -u

This command will write the value 0xBF to the lfuse and set CKOUT.
For a breakdown the "-U" command above, the command:

• selects the lfuse memory for the operation
• writes (use r for read and v for verify)
• the value 0xBF
• in immediate mode (i.e. write the value specified directly)

"-u" turns off safe mode which should enable the actual write.

And there we have it. Your Arduino should now be in a state where we can move onto the more advanced chapters of Matt's book.

Next time we are going to do exactly that, I hope you've enjoyed this post.
Until then, happy hacking!
-(e)

p.s. If you get stuck, I can attempt to help you out, circle me on G+ and send me a message via Messenger, or post a comment and I'll see what I can do.


Advanced Notes:

Perhaps you have a different model of Arduino? (e.g. ATMega168 e.t.c.):

The "-p m328p" switch for AVRDUDE specifies what chip your Arduino has. The "m328p" value is valid for the Arduino UNO and several other models, but will have to be changed for alternative models.

In this case, when using the fuse calculator please input your values for lfuse, hfuse and efuse into the fuse calculator, ensure that you have the correct AVR chip selected and note the change in the lfuse value when CKOUT is selected. The point here is that we wish to change ONLY this value. You can also confirm default board fuse settings in the "boards.txt" file located in the "hardware\arduino" directory of the Arduino IDE installation.

AVRDUDE has many other switches and supports many other programmers. I would suggest that you check out the command line in the documentation.

Implementing Artcfox's TLC5940 code on an Arduino, Part 1

In a previous post I explained how to port Matt Pandina's TLC5940 library to work with an Arduino. While that post would allow you to port the code and flash it to an Arduino I didn't go into detail on getting the code to work in an actual circuit.

+Al McElmon prompted me to get my arse into gear and so:

Over the next couple of posts I'm going to do exactly that by referring to some of the chapters and code from Matt's book and providing code and schematics that should build working examples.

This first post will focus on Chapter 3. Lets kick off with a wiring diagram:



As far as the code goes, I have used the code from Chapter3 in the zip file that can be found on Matt's site
You will need to create:

• An Arduino project file (.ino for the Arduino IDE 1.0+) with the following contents:

extern "C"
{
  #include "main.h"
}


void setup()
{
}

void loop()
{
  themain();
}

• Create the following main.h file:

#ifndef __MAIN_H
#define __MAIN_H

#define PB0 PINB0
#define PB1 PINB1
#define PB2 PINB2
#define PB3 PINB3
#define PB5 PINB5


#define PC0 PINC0
#define PC1 PINC1
#define PC2 PINC3

#define PD1 PIND1
#define PD3 PIND3
#define PD4 PIND4
#define PD5 PIND5
#define PD6 PIND6
#define PD7 PIND7

int themain(void);

#endif

• Copy the main.c from the "/code/ch3" dir in Matt's source archive.
• Edit the main.c file to add #include "main.h" after the first two includes:

#include <stdint.h>
#include <avr/io.h>
#include "main.h"

• And finally rename the function "int main(void)" to "int themain(void)"

And you should be good to go. The CH3 code doesn't do too much apart from turning a few channels on (see the gsData array for details). If you connected a single LED as per the diagram then it should light.
In a future post I will look into some more exciting code, re-programming the fuses on the Arduino to enable the clock output and other bits necessary in order to get Matt's full library working.
Until then, happy hacking!
-(e)