Default mbed pwm doesn't have enough resolution at high frequencies, thats why I implemented VNH5019 Motor carrier with FastPWM.
Fork of VNH5019 by
VNH5019.h
- Committer:
- mbedoguz
- Date:
- 2017-11-30
- Revision:
- 9:1709d9b034f7
- Parent:
- 8:1458b4da7e56
- Child:
- 10:829d36e2de02
File content as of revision 9:1709d9b034f7:
#include <mbed.h> #include <FastPWM.h> class VNH5019 { public: VNH5019(PinName INA_, PinName INB_, PinName ENDIAG_, PinName CS_, PinName PWM_); // set motor speed from -1.0 to +1.0 void speed(double Speed); // stop (no current to the motors) void stop(); // Brake, with strength 0..1 void brake(float Brake); // returns the current through the motor, in mA float get_current_mA(); // returns true if there has been a fault bool is_fault(); // Clears the fault condition // PRECONDITION: is_fault() void clear_fault(); // disable the motor, and set outputs to zero. This is a low power mode. void disable(); // enable the motor. void enable(); // set the PWM period of oscillation in seconds void set_pwm_period(int p) { PWM.period_us(p); } private: void init(); DigitalOut INA; DigitalOut INB; AnalogIn CS; FastPWM PWM; }; // Helper class for the Pololu dual VNH5019 motor shield. // The default constructor uses the default arduino pins. // The motors can be accessed either by .m1 or .m2, or by operator()(i) where i is 1 or 2. class DualVNH5019MotorShield { public: // default pin selection DualVNH5019MotorShield(); // Default pin selection. // User-defined pin selection. DualVNH5019MotorShield(PinName INA1_, PinName INB1_, PinName ENDIAG1_, PinName CS1_, PinName PWM1_, PinName INA2_, PinName INB2_, PinName ENDIAG2_, PinName CS2_, PinName PWM2_); // returns the given motor object, 1 or 2. VNH5019& operator()(int m); VNH5019 m1; VNH5019 m2; }; inline void VNH5019::stop() { INA = 0; INB = 0; PWM = 0.0; } inline void VNH5019::brake(float Brake) { // normalize Brake to 0..1 if (Brake < 0) Brake = -Brake; if (Brake > 1.0) Brake = 1.0; INA = 0; INB = 0; PWM = Brake; } inline float VNH5019::get_current_mA() { // Scale is 210mV per A // Scale factor is 3.3 / 0.210 = 15.7142 return CS.read() * 15714; } inline bool VNH5019::is_fault() { return false; } inline void VNH5019::disable() { } inline void VNH5019::enable() { }