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Best practices for Arduino I/O selection

colporteur

I'm currently working on a project using an Arduino knock-off Mega board. I discovered during prototype board development and testing an issue using I/O' 0 and 1. I found I could not control the output within my script. From online research, I discovered if I was using serial communication then I should avoid using those two I/O's. I wonder what other gotcha's don't know about?

I confess I am way down the scale of Arduinos knowledge. I label myself more of a resurrectionist rather than a programmer. I adapt code and solutions I find to solve my problems. Rarely if ever, have I built from scratch. This leads me to the title line "Best Practices for Arduino I/O selection". Are there any resources that provide this type of guidance? Are there I/O's to avoid and others that are better for a specific function?

I realize some I/O's are for specific purposes. I'm just thinking are there best practices using I/O's. I read the review posted on the site of this new book and thought maybe that has some suggestions. I'm looking for member experience.

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  • I've been caught out with this type of problem when using the Arduino IDE with a board I'm unfamiliar with so I can relate. In your case, the pins with the labels 0 and 1 on the silkscreen will cause a conflict since they also have RX and TX beside them which are used for the serial terminal.  The Arduino reference documentation (as well as the material Dave linked) covers this as shown in the excerpt below.

    image

    But even here they don't state that pins 18 and 19 are set up using Serial1 as opposed to plain Serial for pins 0 and 1.  For that you have to look in the Serial.begin() documentation and it is also shown on the silkscreen.  So the information is spread about.

    The Arduino documentation is pretty good about specifying these things for the Uno in the documentation but the further you stray from that model the less likely that is to be so.  There are so many different processors that use the IDE now (many not even developed by Arduino) it isn't possible to cover them all in one place and it is necessary to pay close attention to the board pinout.  By the time you get to some of the Espressif boards, all bets are off.  Some of the silkscreens are awful and there is only generic information at best.

    The sources that  gives are as good as any I know of along with the documentation in the Arduino reference.  But it is hard to avoid unexpected issues and use of google, especially when using a new board.  Boards with daughterboards/shields having sensors, screens, buttons, and such are often problems as they take away pins.

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  • I've been caught out with this type of problem when using the Arduino IDE with a board I'm unfamiliar with so I can relate. In your case, the pins with the labels 0 and 1 on the silkscreen will cause a conflict since they also have RX and TX beside them which are used for the serial terminal.  The Arduino reference documentation (as well as the material Dave linked) covers this as shown in the excerpt below.

    image

    But even here they don't state that pins 18 and 19 are set up using Serial1 as opposed to plain Serial for pins 0 and 1.  For that you have to look in the Serial.begin() documentation and it is also shown on the silkscreen.  So the information is spread about.

    The Arduino documentation is pretty good about specifying these things for the Uno in the documentation but the further you stray from that model the less likely that is to be so.  There are so many different processors that use the IDE now (many not even developed by Arduino) it isn't possible to cover them all in one place and it is necessary to pay close attention to the board pinout.  By the time you get to some of the Espressif boards, all bets are off.  Some of the silkscreens are awful and there is only generic information at best.

    The sources that  gives are as good as any I know of along with the documentation in the Arduino reference.  But it is hard to avoid unexpected issues and use of google, especially when using a new board.  Boards with daughterboards/shields having sensors, screens, buttons, and such are often problems as they take away pins.

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