digitalWrite not works

Hi, using digitalWrite(13, HIGH); from a sample code LED blink on board does not have effect in my code ; i.e. LED still be off.

My code comes from SD datalogging sample and works perfectly.

In the setup() function a pinMode(13; OUTPUT); directive was entered and after
digitalWrite(13, HIGH); was entered too.

No compiling error was found and code gone to my ARDUINO UNO perfectly with SD gestures without errors but LED on board still not have effect.
Using a separate code from IDE samples i.e. led blink, shows that there are not hardware problem thus LED behaviour is lighting and off alternating.

Any suggest will be appreciated thanks.

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Mark

antonio1234:
Hi, using digitalWrite(13, HIGH); from a sample code LED blink on board does not have effect in my code ; i.e. LED still be off.

Don't try to use pin-13 TWICE for different things!

When using the SD library with an UNO board, then pin-13 will be used for the "SPI-clock" signal!

You cannot use the same pin to control your LED as you like!

SOLVED!

thank you so much, i agree with you.
Now after my misunderstanding evidence another pin must be use,
so facing pin 8 is a good idea that works.

I've really appreciated your interest,
my best greetings!