The processor is outputting PWM voltage to some motor controller, duty cycle 100.
1.If I check with a multimeter I can see the MCU pin out is connected to the motor controller pin .
2.When I check voltage, on the MCU pin, there is 3.3v, on the motor control pin there is 0 .
I have the same thing for 2 different pins with this chip (TB6621 HBRIDGE).
How can 2 pins that are shorted ( I hear the multimeter sound and see r=0) have different voltage in relation to ground ??
gil22:
1.If I check with a multimeter I can see the MCU pin out is connected to the motor controller pin .
2.When I check voltage, on the MCU pin, there is 3.3v, on the motor control pin there is 0 .
After you measure 3.3V at the mcu output pin..... you should keep your (negative) black coloured multimeter cable terminal at the same point..... do not remove it. Bring only the red multimeter cable terminal to the new measurement point.
If you did happen to put your negative multimeter at a different point for your two measurements...... then it's likely that one of the pins which you 'think' is electrically connected to the other 'ground' pin ....... is not actually what you thought. In other words, make sure your motor controller negative terminal is electrically connected to the mcu negative terminal.
I've encountered a very strange problem.
Always try to avoid classifying things as 'strange' unless various experienced people in the field have properly checked out the situation and deem it to be truly strange. For this case, just treat it as... 'measurement assistance required'.