Re: [Flashforth-devel] UNO lockup

[Mikael N. <mik...@fl...>]

I did some tests on my Arduino UNO board. 

If the brown out reset is disabled and I quickly do power on/off,  a lot
of random flash and eeprom  errors occur. 

With the brown out reset enabled (any voltage), there are no errors. 

So it seems definitely recommended to have the brown detection enabled
Probably the 4.5 V value should be the safest value. Extended fuse =
0xFC on the Atmega 328. 

BR Mikael 

On 2022-03-23 16:12, Mikael Nordman wrote:

> Ed, 
> 
> Setting the brown-out reset bits to %100 (4.3 volts) may prevent the corruption. 
> 
> From the datasheet: 
> 
> "A Flash program corruption can be caused by two situations when the voltage is too low. First, a regular write sequence to the Flash requires a minimum voltage to operate correctly. Secondly, the CPU itself can execute instructions incorrectly, if the supply voltage for executing instructions is too low." 
> 
> "Keep the AVR RESET active (low) during periods of insufficient power supply voltage.
> This can be done by enabling the internal Brown-out Detector (BOD) if the operating volt-
> age matches the detection level." 
> 
> BR Mikael 
> 
> On 2022-03-23 10:02, Ed wrote:
> 
>> I did some more testing involving more boards across several FF versions with no real conclusion.  Results attached. 
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Mikael