I loath to post this so called question because frankly, as a very smart friend of mine one said (paraphrased) .. it's impossible to answer a question incorrectly asked.
And I'm not entirely certain what to ask.
Still first week. I can define an individual pin as in or out, and read or write accordingly.
I could probably even write my eventual project using entirely individual digititalRead/Write (X, Y); commands .. but it would be ridiculously clumsy and exceedingly bloated.
There must be a way to initialize a group of pins as as string or variable.
I'm going through various tutorials but have yet to glean how.
For example, I want to define (an arbitrary) four pins as a BCD output, and then send a single 4 bit parallel word.
Once again .. I know I'm not asking a clear question, but I don't quite know how.
To further expand, the AVR microcontroller family was created by guys who thought the hardware should be made in a way that makes writing code for it in C easy, so everything on the microcontroller has a named constant. However, this is an advanced topic and one that Wiring (precursor to Arduino) discovered very early on solved a lot of headaches, so for a first project, using pinMode(), digitalRead() and digitalWrite(), is the way to go, despite it being clunky. I can tell you from experience, direct port manipulation is not only lighter in code, but also executes much faster.
If you're sending four bits in parallel, you still almost certainly need a clock (strobe) signal to say to the far-end "the data is ready to read", so unless absolute speed is the determining factor, you could still put the four data pins on different ports and use digitalWrite, because although
direct port manipulation is not only lighter in code, but also executes much faster.
I could probably even write my eventual project using entirely individual digititalRead/Write (X, Y); commands .. but it would be ridiculously clumsy and exceedingly bloated.
Well, somehow I've been doing that for several years now, and would not describe the result as "clumsy" or "bloated". Perhaps you are imagining your program as it would be without code factoring.
Sorry, I haven't been around in a while. I could write a bad country song with these holidays .. small stroke and one of my dogs died.
Just reading your replies now - much thanks, seems as if I did compose a useful question after all.
I've hooked up a pair of HDSP-0962 displays and will practice playing with port functions.
Aarg .. I'm still dealing with the very basics of the language.
My eventual project goal is to use a pair of HPDL-1416 displays and a parallel RTC chip to fashion a ridiculous watch. It just seems to me as if it would take thousands of lines to manipulate the pins individually, where grouping them into ports would be a much more direct approach.
Either way, at the moment I'm still just learning the capabilities of the device.
Perehama - will definitely check out that manual link.
I tend to favour books over a computer screen .. you can dog ear corners, add notes in the margins, etc. Somewhat ironically, until recently I spent 30 years repairing copiers and printers - so I never owned one with a thousand available! This recently rectified, so printing manuals will likely help with the learning curve.
It just seems to me as if it would take thousands of lines to manipulate the pins individually, where grouping them into ports would be a much more direct approach.
int n = 500; int e = 0; int r = 0x0C; int p = 3;
void setup() {
DDRD = B11111100;
}
void loop() {
PORTD = e; // write "0";
delay(n);
PORTD = B00000100; // write "1";
delay(n);
PORTD = 0x08; // write "2";
delay(n);
PORTD = r; // write "3";
delay(n);
PORTD = B00010000; // write "4";
delay(n);
PORTD = B00010100; // write "5";
delay(n);
digitalWrite (p, HIGH); // change "5" to "7" by altering B bit of display;
delay(n);
}
Okay, this is fun! You guys have been incredibly helpful. Still just mucking about, but I feel as if I'm getting a feel for it. I have a 4 bit display weighted 8,4,2,1 on pins 5 through 2 and just getting the feel for what I can do with variables and declarations .. and the language in general. Miles to go, but it no longer looks like Sanskrit. I'm a bit stoked tonight.
Golam - I particularly like your example. I understand what it's doing, but not having much luck making it work yet. Will have to play with the syntax a bit and read up on for-next loops - but this will be quite helpful addressing consecutive pin groups.
BCD.