I teach programming and robotics to high school students with very little electronics background. (Read: if they can destroy a board they will.) They are about to start controlling simple, low-current devices (LEDs, relays, piezo buzzers, etc) with the Teensy 3.0 and I want to make sure I have the correct current data for the pins. (I've done a lot of searching but I get a variety of answers and was hoping that something this basic was listed on the PJRC site but I couldn't find it.)
Am I correct in thinking that the maximum total output current of all I/O pins is 100mA?
Is this the recommended maximum or the absolute-if-you-go-over-this-the-board-will-be-destroyed maximum? The data sheet (http://pjrc.com/teensy/K20P64M50SF0.pdf) seems to indicate that the absolute maximum is 155mA. (Again, I don't care what the value are, I'm trying to prevent 34 students from destroying 34 Teensy 3.0's!)
Am I correct in thinking that each I/O pin can safely handle a recommended maximum current of 9mA?
Am I correct in thinking that the absolute-if-you-go-over-this-the-pin-will-be-destroyed maximum current for each I/O pin is 25mA?
In other words: the Teensy 3.0 can drive an LED with 9mA all day long, but driving it with a current of 20mA risks damaging the pin, and driving a 30mA LED will certainly damage the pin.
Do I understand the physics correctly?
Finally, are the current levels different for analog and digital pins?
Thanks for your input.
Am I correct in thinking that the maximum total output current of all I/O pins is 100mA?
Is this the recommended maximum or the absolute-if-you-go-over-this-the-board-will-be-destroyed maximum? The data sheet (http://pjrc.com/teensy/K20P64M50SF0.pdf) seems to indicate that the absolute maximum is 155mA. (Again, I don't care what the value are, I'm trying to prevent 34 students from destroying 34 Teensy 3.0's!)
Am I correct in thinking that each I/O pin can safely handle a recommended maximum current of 9mA?
Am I correct in thinking that the absolute-if-you-go-over-this-the-pin-will-be-destroyed maximum current for each I/O pin is 25mA?
In other words: the Teensy 3.0 can drive an LED with 9mA all day long, but driving it with a current of 20mA risks damaging the pin, and driving a 30mA LED will certainly damage the pin.
Do I understand the physics correctly?
Finally, are the current levels different for analog and digital pins?
Thanks for your input.