Bournetoride patch pwm

[Bournetoride]

Description: Add PWM output to Dimmer Pin

Related issue (if applicable): fixes #

Checklist:

• [x ] The pull request is done against the latest dev branch
• [x ] Only relevant files were touched
• [x ] Only one feature/fix was added per PR.
• [x ] The code change is tested and works on core 2.3.0, 2.4.2, 2.5.2, and pre-2.6
• [x ] The code change pass travis tests. Your PR cannot be merged unless tests pass
• [x ] I accept the CLA.

[colinl]

Can I have a detailed description of what this does please?

[Bournetoride]

It sends a PWM signal based on power output from PID instruction, I use it to drive a PWM fan motor. Using Dimmer command it is sent to whichever pin is defined as PWM1.

[colinl]

OK, that looks reasonable. Just a couple of points.

I haven't used pwm, but I see you are scaling the pid output to the range 25 to 75, is that what is required for pwm?

In the section at the start of the file, could you comment out the line starting
#define PID_USE_PWM
That should not be the default if someone uses the file and does not specifically configure that option.
Also there is a commented out line that can be removed
//dimmer = pwm_power;

Also could you revert the change to user_config_override_sample.h please, that file is not modified on the branch.