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Topic: Arduino UNO: D11, D12 and D13 after reset pulse (Read 717 times) previous topic - next topic

ghiblipg

Hi

I notice there is a 3 pulses/spikes on the UNO D11 (MOSI), D12 (MISO) and D13 (SCK) each time i press the reset button.
This is not observed in other IOs.
All above IOs are set as output.

D11 - 1.5V spike, 124ms between each
D12 - 3V spike, 124ms between each
D13 - 5V pulses, ~8Hz, 124ms pulse width (50% duty cycle).

Anyway to prevent this?
I used these pins at OUTPUT to trigger another circuits.
This caused false trigger when power up or reset.

CrossRoads

You could try 1K to 5K to 10K pullup or pulldown resistors so the pins are not floating immediately after the reset.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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