Grumpy_Mike:
Yes. Plus Arduino ground to external power ground.
Think of it like this. They are not two things but PWM is a way of using a TTL signal.
TTL is a signal an Arduino output, PWM is something you do to that signal.Do not send technical questions as a personal message.
Thanks now i got it.
Vcc to 12v external power +
and
GND to external power - and GND of arduino.
Then
PWM is connect to D11 pin of arduino
Is there anything to change in grbl?
(extremely Sorry for the personal message)