Arduino newbie - do sketches stay in the board during power down?

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1

Hi All,
Just starting out with Arduino and have had a scan of the online information, and the arduino for dummies book, but have not been able to determine whether the arduino board retains uploaded programs when powered down (eg Flash memory), or whether the onboard memory is volatile, so that software has to be re-uploaded each time the board is powered up.
TIA
EdT

2

Flash is non-volatile, so it remains after power down. On power up it starts over, re-initializes and executes setup() and then loop()s.

3

Yes, it keeps the program when power is removed.

(and will start running it when you apply power again).

4

~~Just for the future... if you use the internal EEPROM memory to store data, then you will lose whatever data you stored in there, as it is volatile memory.~~[/u]
EDIT - You won't lose EEPROM data either... :* But still, it can only be used a finite number of times, and tricks in software can help with not writing unless absolutely necessary, and spreading out the wear on the cells.
You can also only use it finite amount of times before it fails.

5

@jtw11:

Please read Arduino Memories | Memories of an Arduino | Adafruit Learning System

Ray

6

Thanks to all - very informative!
Ed

7

jtw11:
You can also only use it finite amount of times before it fails.

It's a LOT of times though...