You can control servos (small ones) from a Micro:Bit directly. Following a link from the David Whale (Twitter @whaleygeek) , thank you, took me to a Kitronik blog post, https://www.kitronik.co.uk/blog/using-bbc-microbit-control-servo/, which has the answer.
The code uses Microsoft Blocks taken from the post, runs the servos 180 degrees and back again, when button A is pressed. It does exactly what it should. I am also using the Tower Pro SG90 servo.
Can it be replicated in Micropython? This is a new mini project, there seems to be little out there yet on how do this but the best so far is this video by PHILG2864:
The closest I have is the following, it is essentially there.
from microbit import *
Setting the time period to 20ms pin0.set_analog_period(20)seems by experiment (and used in the video above) to be best value so far. The reason for pin0.write_analog(1) set to 1 instead of 0, 0 seems to stop the whole thing.
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