Arduinio pro mini max output pins

Other Hardware LEDs and Multiplexing
1

Hi,

I would like to use the pro mini board to blink max ammount of signal leds (needed more than 14 and each pin needs to output 0v, all leds are common anode). can you please advice how many leds/ outputs pins i can use with this board only for this purpose?

Thanks

2

Read up on led matrix and/or charlieplexing.

You will have to consider the maximum current that a pin can sink/source, the maximum current that can flow through the microcontrollers port and the maximum power that can flow through the microcontroller's internal Vcc and GND.

Note that a LED does not have a common anode, it has an anode and a cathode; so you probably have either a RGB led or you have a display.

Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for advice on (nor for problems with) your project :wink: See About the Installation & Troubleshooting category.

3

That uses the ATmega 328 processor, the same one used in the Uno and Classic Nano.

This implies that they are not single LEDs, so what sort of LEDs are these.
The normal absolute values apply.

Abs
Abs1690×546 72.5 KB

Note that these figures are where damage starts to occur, so you can't run them at 40mA per pin. The normal working rate is 20mA. Although I would consider 30mA to be the maximum usable current, I know others disagree. Note that any current through an output pin draws that current from the Vcc (positive) or ground of the power supply so that imposes an overall limit in any case. Note that you also need about 30mA from the supply to run the rest of the processor.

However you can't just use every pin at that, there are conditions based on what port these pins are on.

Conditions
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Note these restrictions are for both sourcing and sinking current, and unusually you can source more current than you can sink.

This link tells you what ports each pin of the Arduino is on.
Port Manipulation

4

My question regards to The max outputput pins i can use to operate leds (current is not relevant, i am using an external 5v for the leds max 5ma each).

If counting all the Digital (2-13) + analog (A0-A7), In total 20 output pins? or i am missing others that can also can be use as output pins?

5

You can't use A6 and A7; they are analog input pins only. If you don't have a need for serial communication, you can use D0 and D1.

Uploading will be tricky if you use all pins and you will have to disconnect whatever is using the pins that you use for upload (either D0/D1 or the SPI pins).

6

If you are using pins on the Arduino to control anything then current is always relevant no matter what the source of power is. Even if is to know you are within the limits.

7

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