Creatorskit 8x8 led matrix example: maximal current too high?

1

Dear All,

I have a question concerning the 8x8 matrix array example of the creators kit booklet (p50-53, a 2013 copyright on the back).

There 8 pins are used for 8 row sinks, and 8 pins are used for
8 column sources. The LED resistors are chosen to be 220Ohm.
Assuming the Red LED dropping ~2V we have a current of
(5-2)V/ 220Ohm ~ 14mA per LED,
If we now switch on all column pins the current low pin will have
to sink 8 * 14 mA =112 mA, which is far above the 40mA max. current
per pin.

I couldn’t find reports of users burning their Atmel chip, so I
wonder whether I’m missing something.

Best regards,
YB

2

5 More Ways to Destroy an Arduino - at 5:00 min -

5 Ways to Destroy an Arduino

3

Dear Old_Grey,

indeed these clips are pretty nice and clear
and I can only agree.

Still I wonder why the Creatorskit manual suggests to overload the Arduino.

Best regards,
YB