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Why do so many MCUs specify what kind of motors they work with? For example: http://www.microchip.com/pagehandler/en-us/technology/motorcontrol/

Surely, the MCU has no concept of a motor and it simple outputs a PWM signal which can then be interpreted by anything (e.g a VFD).

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    \$\begingroup\$ they are specifying the types of motors. For instance 3 PWM channels can drive 3 DC motors or a single BLDC. In addition to PWMs there are sometimes dedicated peripherals for encoder and/or Hall sensors input. Or PWM-synchronized ADC input, which is used for precise current control. \$\endgroup\$
    – Eugene Sh.
    Dec 21, 2015 at 21:58

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Surely, the MCU has no concept of a motor and it simple outputs a PWM signal which can then be interpreted by anything (e.g a VFD).

PWM output from an MCU could be used with anything that accepts it. However some MCUs have specific features to handle motors such as bi-directional bridge drive, current limiting and fault lockout.

Different motors have different drive requirements. A brushed DC motor only needs one PWM output to control speed in one direction, but 3 phase BLDC motors need 3 PWM outputs as well as 3 other phase outputs and 3 differential analog inputs to monitor rotor position.

If the MCU cannot do it alone then external components are required. When that gets to the point of being an entire ESC or VFD the MCU is no longer a motor controller, it's just a signal generator.

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Marketing thinks potential customers are dumb (they're often right) and wouldn't think of using a feature in a particular way unless you explicitly tell them. Also, that page seems to be more about the layered software, which will be more specific to type of motor and control scheme.

You are right though, PWM is PWM, and you can use it in many different ways. Some PWM controllers are optimized for or have extra features for specific tasks, but that usually doesn't prevent them from being used to put out ordinary PWM.

For example, there are PWM modules for dsPICs that are specifically intended for driving H bridges. That can be tricky, and extra hardware in the PIC, like dead time control, can be really useful for such cases. Again though, if you just want basic PWM out, any PWM generator can do that, whether it can do other things too or marketing says it's "ideal for ...." some specific uses or not.

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