BBS:      TELESC.NET.BR
Assunto:  Re: PI PICO W minimum voltage..
De:       Pancho
Data:     Thu, 14 May 2026 22:27:59 +0100
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On 5/14/26 22:17, The Natural Philosopher wrote:
> On 14/05/2026 18:08, druck wrote:
>> On 13/05/2026 14:06, The Natural Philosopher wrote:
>>> On 13/05/2026 12:12, druck wrote:
>>>> On 12/05/2026 14:04, The Natural Philosopher wrote:
>>>>> I measure at the far end of the chain
>>>>
>>>> How? Multimeter, USB power measuring dongle, oscilloscope.
>>>>
>>> Sigh
>>>
>>> The Pi PICO W has three ADCs on board and one is connected directly
>>> to VSYS by a voltage divider. I transmit that data every time the
>>> device successfully activates.
>>
>> I'm not sure I trust something to measure it's own voltage, when it
>> might be experiencing low voltage.
>>
> That is probably because you have not understood the first thing about 
> how a PI PICO W is constructed.
> 
> It has its own onboard buck/boost regulators and the ADC is driven from 
> a stabilised 3V line
> 
> The rest of the chip runs on a less well regulated 3.3V.
> 
> The chip runs down to 1.8V
> 
> The ADC is not set up to 'measure its own voltage' but that of the 
> incoming voltage TO the chip.
> 

FWIW my rpi4 is able to give low voltage warnings, seemingly reliably.


--- PyGate Linux v1.5.14
 * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

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