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DIP package meaning it's easier to plug/unplug into a breadboard. 5V operation mean you can just plug it in to USB power directly without any voltage regulator

DIP package meaning it's easier to plug/unplug into a breadboard. 5V operation mean you can just plug it in to USB power directly without any voltage regulators. High current sink/source capable pins, meaning you can drive LEDs and other stuff directly. Pins with builtin schotky diodes meaning you can power the thing from AC power sources. The Arduino ecosystem with many available projects for which moving to an ARM chip would bring no benefits.

dotancohen 4y ago
> Pins with builtin schotky diodes meaning you can power the thing from AC power sources. Can you elaborate on this? I don't think that one could power an Arduino from 240v 50hz AC, but it doesn't seem like you are referring to the use of a transformer.
- gzalo 4y ago
  Well, the clamping diodes that are present in all I/O pins are supposed to be used only for ESD protection. I think they were refering to the fact that some people have used them (and a quite big series resistor) as a "cheap" way to connect them to AC directly. There's even a application note (from 1997!) mentioning this: http://ww1.microchip.com/downloads/en/AppNotes/00521c.pdf http://ww1.microchip.com/downloads/en/AppNotes/00521c.pdf Obviously the device loses its galvanic isolation and should be kept in an enclosure that can't be touched. This can also be used for "accepting" 5v inputs in 3.3v devices, provided that the clamping current doesn't support the maximum allowed. Other microcontrollers don't always define maximum values for those currents, so it might be harder to use them like that.
  - dotancohen 4y ago
    Interesting, thank you. That's not an experiment I would do, but it is interesting to know nonetheless.
- ChuckNorris89 4y ago
  AC doesn't necessarily mean 110-240V mains voltages, it just mean alternating current. It could be 12V from a transformer or some other induction coil like RFID or Wireless charger.
  - dotancohen 4y ago
    Sure, but is that ever actually encountered in practice?
    - ChuckNorris89 4y ago
      In hobby/student projects, yes, very often. Maybe even in some cheap white goods. Otherwise they wouldn't have bothered publishing application notes on it. It's awesome to just hook up a random coil you found/wound to the pins of an AVR and watch it just work.
      - dotancohen 4y ago
        Terrific, thank you! I've never seen this, but it's good to know if I ever come across such a device.
bacon_waffle 4y ago
> High current sink/source capable pins, meaning you can drive LEDs and other stuff directly. FWIW, it's common to drive LEDs from GPIO pins on other micros too. From a quick look at the SAMD21 datasheet for instance, GPIO pins are rated to sink up to 10mA which will make a typical indicator-type LED probably too bright for indoor applications. > The Arduino ecosystem with many available projects for which moving to an ARM chip would bring no benefits. My question (which you and others have answered, thanks!) was in the other direction: the Arduino ecosystem largely works for these 32-bit chips too; what benefit is there in moving to an AVR?

dotancohen 4y ago

> Pins with builtin schotky diodes meaning you can power the thing from AC power sources. Can you elaborate on this? I don't think that one could power an Arduino from 240v 50hz AC, but it doesn't seem like you are referring to the use of a transformer.

gzalo 4y ago
Well, the clamping diodes that are present in all I/O pins are supposed to be used only for ESD protection. I think they were refering to the fact that some people have used them (and a quite big series resistor) as a "cheap" way to connect them to AC directly. There's even a application note (from 1997!) mentioning this: http://ww1.microchip.com/downloads/en/AppNotes/00521c.pdf http://ww1.microchip.com/downloads/en/AppNotes/00521c.pdf Obviously the device loses its galvanic isolation and should be kept in an enclosure that can't be touched. This can also be used for "accepting" 5v inputs in 3.3v devices, provided that the clamping current doesn't support the maximum allowed. Other microcontrollers don't always define maximum values for those currents, so it might be harder to use them like that.
- dotancohen 4y ago
  Interesting, thank you. That's not an experiment I would do, but it is interesting to know nonetheless.
ChuckNorris89 4y ago
AC doesn't necessarily mean 110-240V mains voltages, it just mean alternating current. It could be 12V from a transformer or some other induction coil like RFID or Wireless charger.
- dotancohen 4y ago
  Sure, but is that ever actually encountered in practice?
  - ChuckNorris89 4y ago
    In hobby/student projects, yes, very often. Maybe even in some cheap white goods. Otherwise they wouldn't have bothered publishing application notes on it. It's awesome to just hook up a random coil you found/wound to the pins of an AVR and watch it just work.
    - dotancohen 4y ago
      Terrific, thank you! I've never seen this, but it's good to know if I ever come across such a device.

bacon_waffle 4y ago

> High current sink/source capable pins, meaning you can drive LEDs and other stuff directly. FWIW, it's common to drive LEDs from GPIO pins on other micros too. From a quick look at the SAMD21 datasheet for instance, GPIO pins are rated to sink up to 10mA which will make a typical indicator-type LED probably too bright for indoor applications. > The Arduino ecosystem with many available projects for which moving to an ARM chip would bring no benefits. My question (which you and others have answered, thanks!) was in the other direction: the Arduino ecosystem largely works for these 32-bit chips too; what benefit is there in moving to an AVR?