What is different about counters?

lardom

I normally can control transistors with an i/o pin and a pull-down resistor. When I tried to use one of the prop's counters for PWM I had to connect the emitter to propeller ground before the transistor would work. I guess that means the counters have lower signal voltage. I know there is something I don't see yet but I would like someone to help me understand why I had to use a propeller ground before I could switch on a transistor with a counter signal. Thanks

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Phil Pilgrim (PhiPi)

You always have to have the emitter at logic ground to switch an NPN transistor reliably -- not just when using counters. The "high" output from a Prop counter is 3.3V, with the same drive capacity as a steady output.

-Phil

lardom

Thanks, Phil.

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