3.3v on reference

[espruino-discuss3]

Posted at 2014-06-29 by Alex

Hi Gordon,

Today I tried using MosFETs with the espruino and I used the pins that do not say 3.3v on the reference page, assuming that those were 5v.. could your verify that all pins give 3.3v? Also, could you explain why there are only some labeled with 3.3v?

Thanks!

Alex

[espruino-discuss3]

Posted at 2014-06-29 by azrobbo

I can answer your question regarding the meaning of the 3.3v label on the reference diagram.

The pins labeled "3.3v" are only tolerant of 3.3v input voltage. Whereas, the pins without the "3.3v" label are tolerant of up to 5v input voltage. The data sheet has a pinout table on p 30-35, where this can be verified.

I do not believe the output voltage is any different on those pins, but I'll defer that to Gordon.

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Posted at 2014-06-30 by DrAzzy

Yeah - all the pins can output max of 3.3v.

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Posted at 2014-06-30 by Alex

Hi Guys,

Thank you for the explanation. I guess new mosfets it is :).

Regards,

Alex

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Posted at 2014-06-30 by @gfwilliams

You have one more option:

Take a pin that doesn't say 3.3v, and then use pinMode(pin, 'opendrain') and use something like a 4.7k resistor to pull the pin up to 5v. That way you can get a 5v output voltage for the FET.

Hope that helps!