Fundamental programming

[mortenbo1948]

I do miss some fundamental information.
When looking up all the boards I have purchsed, I can not find uot wether to use the
MCU-pin number or the MCU pin aberrative name or the boards description pin name?
Which is correct?
Sorry confused.

[TomGeorge]

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.

What boards do you have.
If they are Arduino boards, you use the pin names/numbers printed on the PCB, not the controller IC pin numbers.
Reference ALL your pin allocations to the PCB data.
So

pinMode(5, OUTPUT);

Would make pin 5 on the PCB an output.

Or to make your coding easier;

byte outsigPin = 5;
void setup
{
pinMode(outsigPin, OUTPUT);
}

Tom..

[GoForSmoke]

Google "arduino pin map" just to see what comes up. Replace "arduino" with the name of your board if you want the top choices to be about your board.

[GolamMostafa]

The following diagram belonging to Arduino UNO may be helpful.

[mortenbo1948]

It is an ItsyBitsy not found in Aduino.cc
Acording to image, the board via 7, is connected to MCU pin 1
Link:
Pinouts | Introducing Adafruit ItsyBitsy M4 | Adafruit Learning System
Here via7 is the same as #7 - GPIO #7 can PWM ???
So const byte interruptPin = 7; is correct?

But what about A0 etc
byte OUT_SIGNAL_A0 = a0;
pinMode(OUT_SIGNAL_A0, OUTPUT);
analogWrite(OUT_SIGNAL_A0, 50%); //pwm?

It is working now. Running on 3V battery only.
But it must be the Ardino compiler, who know's what board is connected? I guess
Br Cofused

[groundFungus]

How to post an image.

Here via7 is the same as #7 - GPIO #7 can PWM ???
So const byte interruptPin = 7; is correct?

Pin 7 is not a PWM pin.
Pin 7 is not an external interrupt pin.

byte OUT_SIGNAL_A0 = a0;
pinMode(OUT_SIGNAL_A0, OUTPUT);
analogWrite(OUT_SIGNAL_A0, 50%); //pwm?

A0 is not a PWM pin. It is a non PWM pin that can be set to be a digital input, digital output or analog input. 50% will cause an error.

PWM pins are 3,5,6,9,10,11 (analogWrite()).

[TomGeorge]

groundFungus:
Pin 7 is not a PWM pin.
Pin 7 is not an external interrupt pin.
A0 is not a PWM pin. It is a non PWM pin that can be set to be a digital input, digital output or analog input. 50% will cause an error.

PWM pins are 3,5,6,9,10,11 (analogWrite()).

I think you had better read this;

Introducing Adafruit ItsyBitsy M4

To quote one paragraph.

Nearly all pins can do PWM output
All pins can be interrupt inputs

Along the right edge
#0 / RX - GPIO #0, also receive (input) pin for Serial1. PWM output
#1 / TX - GPIO #1, also transmit (output) pin for Serial1. PWM output
SDA and SCL - these are the I2C hardware interface pins. There's no pull up on this pin by default so when using with I2C, you may need a 2.2K-10K pullup on each to 3.3V. PWM output
#5 - GPIO #5. This is a special OUTPUT-only pin that can PWM. It is level-shifted up to Vhi voltage, so its perfect for driving NeoPixels that want a ~5V logic level input. You can use this with our NeoPixel DMA control library to automatically write NeoPixel data without needing any processor time.
#7 - GPIO #7 can PWM
#9 - GPIO #9 can PWM
#10 - GPIO #10 can PWM
#11 - GPIO #11 can PWM
#12 - GPIO #12 can PWM
#13 - GPIO #13 can PWM, is connected to the red LED next to the Reset button

itsy is not a 328.
Tom...

[groundFungus]

itsy is not a 328.

My mistake. Did not look closely. Apologies.

[lastchancename]

...It could be (?)
This where you need to scratch under the hood a bit to reach a fairly advanced topic.

In most IDE / compiler environments there is a lot of ‘abstraction’ going on that allows pins, registers and other stuff to have friendly, memorable names. This includes the ability to call a ‘cow‘ a ‘pigeon’, or any other nonsense required to conform to one architecture in a different environment.
This how many newer boards are accommodated into the existing Arduino ecosystem. It’s not a small thing to grasp.

However this assumes that casual users won’t mingle (or even know about) those two worlds unless they know what they’re doing.

In Arduino IDE land, a lot of that magic happens in boards.txt, and platforms.txt - deep down in the Arduino hardware folder.

Don’t fiddle with those contents unless you save a backup copy and have a pretty good idea what you’re doing!

EDIT: as @pert points out below, I should have mentioned pins.h

[pert]

Pin mapping for this board is done in the itsybitsy32u4 variant's pins_arduino.h:

adafruit/Adafruit_Arduino_Boards/blob/master/variants/itsybitsy32u4/pins_arduino.h

[mortenbo1948]

Thank's replying, but what I do wnant, is some of the attached picture.
which ones is the best I do not know.
But adafruit_products_pro5.png show at least pin-number to be used in programming? I think.
I do not dare to ask ARDINO or ADAFRUIT to create such pictures on all board.
I really do not.
Br

[pert]

You can use the adafruit_ ItsyBitsy_5v.png image you attached:

The pin mapping is the same between the two boards. Vcc and the clock speed is different, but that doesn't affect the pin mapping.