[pbro]

<div>And another quote, this time from Wikipedia, concerning totem pole outputs:
</div><div>

“some push–pull outputs have a third state in which both transistors are switched off. In this state, the output is said to be floating (or, to use a proprietary term, tri-stated).”

So, it sounds like the the Controllino Mini might have tri-stated output, which isn’t a bad idea in any case.

</div>

[pbro]

The following is a quote from page 59 of the Atmel ATmega328P manual.

“If PORTxn is written logic one when the pin is configured as an output pin, the port pin is driven high (one). If PORTxn is written logic zero when the pin is configured as an output pin, the port pin is driven low (zero).”

If this is true for the Controllino also, the output pin should not float if a zero is written to the pin. Of course, the usual error is with the programmer, so maybe I am missing a configuration step.

[pbro]

M. Math, the Mini can handle two external interrupts with no problem. I am not sure what the maximum frequency is, but we have interrupts at about 200Hz on Int0, and 50Hz on Int1.

What may cause problems is noise. Noisey input is common, although if you are testing battery voltage, that might not have noise. If you can, look at the input on an oscilloscope. Good luck…

[pbro]

I am using the Mini for a similar situation; in my case the rotary encoder pulses let us know where cherries are as they move along the sorting line. The encoder is an Autonics E50S8-200-3-t-24, with totem pole output. The B phase is wired to Int0, the Z phase to Int1 and the A phase goes to pin A3 (PC3). The internal pullup resistors are enabled. The input signals are very clean.

However, the output signals on pins D4 and D5 (PB0 and PB1) are not clean. The output pins float when the output value is 0. When the output is 1, the signals are a decent high. I have to include a pulldown resistor (1K) and with the pulldown, the output signals are quite clean. I don’t understand why I need an external pulldown for the ATmega328P pins. If anyone has a suggestion, it would be great.