Aha! Thanks Condemned! PIND instead of PORTD.

Does that stand for Port INput D ?

In the code below if I use digitalRead(6) I can read the logic level on my PortD Pin6. If I use the Led = PORTD & B11000000 statement I do not get bit6 wiggling as I'd expect.

What am I doing wrong?



void setup()
{
    Serial.begin(9600);
    // prints title with ending line break
    Serial.println("Setup starting");
  
    // The Data Direction Register of Port D, don't touch the
    // lower two bits which are serial IO
    DDRD = DDRD | B00111100 ;

}

void loop()
{
    int i = 0 ;
    int iLed = 0 ;
    while (true) {
 
        // iLed = digitalRead (6) ;
        iLed = PORTD & B11000000 ;
        Serial.println("iLed =");
        Serial.print(iLed, OCT);    

"Would a 16 bit Allegro A6276 work for your application? I used two in series for my 5x5x5 LED cube and they worked great. It's avalible in a 24 pin slim DIP package. I bought mine from Newark Electronics and they didn't seem too expensive to me for the functions they provide.

http://www.allegromicro.com/en/Products/Part_Numbers/6276/"

That looks ideal! Thanks. Seems that it is going out of production too, but they are bringing in a new version....

Is there a replacement for STP16CL596?

The DIP version of this chip was ideal for a project I have in mind (tons of LEDs (yawn!)) but I've seen on the WEB that they are out of production?

Does anyone know if this is true, and if it is true is there a replacement out there? It has to be at least 10 bits and hopefully able to drve LEDs at 25ma directly...

I know there are some 74 and 4000 16 bit registers, but not sure that they can drive all 10 leds without overheating...

TIA!

You say:

"I'm not exactly sure how a CCD works, How does this help detect wavelength"

Imagine that the CCD is a long line of light detectors. Imagine you shine a rainbow on the CCD.  A part of the CCD will get red light, a part green light and so on. So the intensity of the different parts gives you the intensity of the different colors.

You can get your "rainbow" from a prism or, possibly, a bit of a broken CD or DVD.

So, I should actually do:

  // Turn analog inputs to digital outputs
  DDRC=0x3F ; // These will be pin numbers 14 .. 19

is that right?

I posted this because I could not find any clear examples of using these pins.

And you say:

 "PC0 thru PC5 map to Arduino A0 (14) thru to A5 (19)."

which I understand, but what is the advised way of naming these pins. 14 ... 19. I can't find the C define for "A0" or PC0.

It took me a bit of time to extract this info from the docs and the board itself, so I thought I'd post it here so any searchers in the future will get there quicker.

This is for the Duemilanove

    //Using Port C as digital output

In your setup:
    // Turn analog inputs to digital outputs
    DDRC=0xFF ; // These will be pin numbers 14 .. 19


In your loop:
    digitalWrite (14, HIGH);  
    // ...etc...  
    digitalWrite (19, LOW);  

These are Port D0 and Port D1, but what else are they used for? Looks like serial comms, but a search of the forum and Arduino website leaves me flumoxed and confused...

I'm not yet using the Arduino pin numbers because I'm thinking in general about data sizes and so on.

Thanks for that link, it was just what I wanted.

So, for the Arduino DueMilaNove
Port B the lower six bits are available for digital IO
Port C the lower six bits are available for digital IO and analog input
Port D the upper six bits are available for digital IO

It seems that sometimes the docs say pin0 when they mean bit0...?

Many thanks for the help.

And my subject line was inaccurate too. Port E indeed!

I think, but I am not sure, that I can use all bits of the three ports as input and output?

Port B has 6 bits
Port C has 6 bits
Port D has 8 bits

Is that true? I don't need MISO and MOSI etc so presumably those 4 bits become free for me to use in Port B.

Basically my question is, can I use all bits of all three ports as digital IO as long as I configure them properly, or is there some hardware of the Arduino which prohibits this?

Thanks for the info and the suggestion too.

I don't know much about the two wire comms, so I'll need to investigate a bit.

Imagine a "master" Arduino (M) which is connected to 2 other "slave" Arduinos (SA & SB).

Imagine that 4 bits of all three Arduino's are connected together in parallel. The master M always has its bits as input. And by default the slaves have their bits configured as inputs.

Imagine that one of the two slaves (say slave A) has to send 4 bit data to the master. Can I make slave B's bits configured as input then output the data from slave A?

Ignore the problem of having two slaves outputting at the same time, that would never happen for mechanical reasons.

From "Getting started with the Arduino" I'm not sure if I can supply my own 5V supply direct to the 5V pin, or whether I should always use the 9V to the 9V in pin?

I ask this because I already have a 5V supply available, and it seems a waste to supply 9V to be reduced to 5.