Hello, I have a code which reads an NFC tag and if a valid tag is present it opens a relay. The code works basically fine. Once deployed it runs for months without issues, then all of a sudden the code stops working. Rebooting the Arduino board (power off / on) and it works again for a couple of m…

Hi Adiforum, I do not see the usual suspects in your code: String (with capital S) Use of millis() combined with unhandled overflow of unsigned long... Could the problem be in your hardware? You could log and check the free memory every day in your code... maybe something is added to stack or h…

[image] adiforum: // Wait for the CRC calculation to complete. Check for the register to // indicate that the CRC calculation is complete in a loop. If the // calculation is not indicated as complete in ~90ms, then time out // the operation. const uint32_t deadline = millis() + 89; Like t…

You coukd save some time by goosing millis() up to a few minutes before it rolls over. Or whatever. Oh yes you can. Declare the variable millis() uses in you own code: extern volatile unsigned long timer0_millis; To set millis(): noInterrupts (); timer0_millis = 4294967295UL - 20000; // 20…

Umm, the OP isn't the one using millis(). It's in the library included. Would this idea still work for them? -jim lee

I'm tempted to say of course it will. I don't know for sure, but… … there's one mechanism somewhere that ticks up the milliseconds counter, the millis() function returns that value so messing with that variable will mess with eveyone's millis(). It is true that it might not be a definitive diagnos…

[image] adiforum: // Wait for the CRC calculation to complete. Check for the register to // indicate that the CRC calculation is complete in a loop. If the // calculation is not indicated as complete in ~90ms, then time out // the operation. const uint32_t deadline = millis() + 89; Hi @ji…

There are a few instances in the MFRC522 library where the code doesn't allow for the millis() rollover every 49.7 days. All the below are from src/MRFC522.cpp . In function PCD_CalculateCRC // Wait for the CRC calculation to complete. Check for the register to // indicate that the CRC calculati…

[image] adiforum: Any idea would be very much appreciated. please show us the wiring between your board and the RC522, measure the length of the wires and tell us more about the environment where you are using your device. As a workaround you could activate the Watchdog. On long term, I wou…

@van_der_decken : good work! So: not the best library... 3 options: 1 fix it 2 find an update 3 find another library... (suggestions?) If @van_der_decken has found all, it is not difficult to fix...

[image] build_1971: Use of millis() combined with unhandled overflow of unsigned long... If you use the proper end time - start time = elapsed time, there is no problem with unsigned integer rollover. The longest elapsed time is 32-bits of time unit be it millis or micros but short of that, …

Code stops working every couple of months

Projects Programming

build_1971 December 16, 2024, 5:19am 8

Hi @jimLee
Where is this coming from?
It us not in the OP...
And the last statement is an example where things can go wrong...
Timers should use subtraction, not addition...

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Code stops working every couple of months

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