Maximum pin-changing rate

[espruino-discuss3]

Posted at 2015-01-15 by Vicary

I have a few hard drive motors lying around. I am thinking of wiring the 4 pins directly to Espruino pins without a driver board, but I wonder if the chip is fast enough to get the motor running at max speed of 7200RPM.

Not sure how to calculate the pin changing rate from chip spec, any ideas?

[gfwilliams]

Posted at 2015-01-15 by @gfwilliams

Well, 7200rpm / 60 = 120 Hz - so yes, that should be fine in terms of speed. Because you're going to be switching in a pattern, you'd have to use JavaScript to do it - and the execution speed will be the thing that slows you down.

I doubt the Espruino pins would provide enough power though (it's only around 20mA @ 3.3v) - not to mention the noise you get from switching inductive loads - so you'd need to use a driver board.