[Microbit-Python] micro bit pin drive current

[Radomir Dopieralski]

I'm not sure about the PyBoard, but the ESP8266 has a "snapback"
circuit on every gpio pin, which basically shorts the pin to the ground
when the voltage on it exceeds 6V. This is supposed to protect it from
ESD, among other things.

I suspect that both the micro:bit and the PyBoard may have similar
circuits on them, as this is a rather standard practice.


On Fri, 2 Sep 2016 21:17:30 +0100
"fresh.bread via Microbit" <microbit at python.org> wrote:

> Interesting, slightly off topic but is the same true of the pyboard?
> 
> > There are no additional buffers on the pins.  The microcontroller
> > will source/sink its maximum current and then the output voltage
> > will begin to drop to keep the current at that maximum (and so act
> > like a current regulator/limiter).
> >
> > On 31 August 2016 at 15:48, fresh.bread via Microbit
> > <microbit at python.org> wrote:
> >> I'm a bit worried by the diagram on the documentation for the
> >> micropython speech module showing a loudspeaker connected directly
> >> to pins 0 and 1 (see
> >> http://microbit-micropython.readthedocs.io/en/latest/tutorials/speech.html)
> >>
> >> What is the maximum drive current for the pins. The processor chip
> >> only seems to be able to sink/source 0.5ma (or 5ma in high current
> >> drive mode) .Are there additional buffers connected to pins 0,1,2
> >> that allow a higher current?

-- 
Radomir Dopieralski