mega2560 bootloader & watchdog

Hello, I've been perusing a number of posts in regards to issues with the watchdog reset timer when using with a MEGA 2560. I recently purchased one from adafruit about a month ago and have been working an a project with it. I was hoping to incorporate the watchdog reset into my project but I am now hesitant because of the reset-loop problem.

Is this issue still current? or has it been resolved...?

mboehm:
Hello, I've been perusing a number of posts in regards to issues with the watchdog reset timer when using with a MEGA 2560. I recently purchased one from adafruit about a month ago and have been working an a project with it. I was hoping to incorporate the watchdog reset into my project but I am now hesitant because of the reset-loop problem.

Is this issue still current? or has it been resolved...?

Hard to answer because there is no way to know what version bootloader your 2560 board has in it. The problems has been known and identified several years ago. And there is a 'fixed' bootloader distributed with the current arduino IDE, but again your board may still have the older bootloader that does suffer the WDT bug.

So you can burn a new bootloader to your board using the stk500boot_v2_mega2560.HEX file or test your board and see if a WDT 'bricks it' in which case you will know you have to reburn the bootloader. :wink:

Got it! Thanks for the prompt reply. If i do need to upload a different bootloader, it looks like i can do so with an uno r3 i have laying around, is this true? I found this link while i was searching around:

It also looks like it may be possible using the arduino IDE. Is that preferable?

Nick’s sketch will work, but ArduinoISP (and many other “programmers”) will not work with the 2560.

Well everything went well and the watchdog timer works perfectly. So if anybody is curious, Adafruit appears to be shipping MEGA 2560s with current bootloaders. Yay!

I'm a little bummed I didn't get to break out the uno.

Sorry mboeh, I'm trying to use wdt on my mega 2560, I read that I have to change the bootloader. Where did you get the fix bootloader? Did you use another arduino to burn it?

AFAIK, Adafruit doesn't change bootloader code on "real" arduinos, so if their MEGAs have the new bootloader, that should mean that all "current" MEGAs have the new bootloader. (Not counting old stock in the pipeline.)