How can I restart a sketch by itself?

Official Hardware Classic Yún
1

Does anyoone know how I can have the sketch trigger itself to re-start, including re-running the setup() and re-initializing all globals... from an action in the sketch itself?

I know I can do something with "reset-mcu" on the Linino side. But, I want to have the sketch itself be able under some catastrophic condition to just restart all over.

Thanks

2

I'm sure there is a better way for doing this, but in the meanwhile, you can run reset-mcu using Process

3

When you wish to reset the chip under sketch control, just enable the watchdog timer and let it time out while you wait in a while loop. This is the only 100% complete way (using only software) to have a sketch start from scratch under user control..

4

great, how do you enable the watchdog?

edit: found it: Watchdog in Arduino Library - or at least support by bootloader - #3 by nickgammon - Project Guidance - Arduino Forum

Never thought it could be so simple.

5

Thanks everyone!

6

Does this work on the Yun ?

Following the link above, I did
#include <avr/wdt.h>
and at the end of setup() I put
wdt_enable(WDTO_2S);
and at the beginning of loop() I put
wdt_reset();

In the loop() I toggle the LED every second and that continues to work, but reading sensors and writing the data to the SD card does not work. If I comment out wdt_enable(WDTO_2S) and wdt_reset() everything works again. I have not done a lot of debugging yet, but just wanted to verify if anybody had the watch dog timer working correctly on Yun.

Thanks, Bjarne

7

To answer my own question, it seems to work just fine on Yun.

Digging a little deeper in my code, I realized that it took more that 2 sec to read all my sensors. That triggered the WDT so the code never reached the point of writing the values to the SD.