Change references to BLDCDriver to FOCDriver in current sense base class

change setPwm function in FOCDriver to accept 3 args, with a default value for the 3rd

Change stepper driver classes to use 3 arg setPwm, ignoring 3rd arg.

created InlineCurrentSenseSync class in lib/currentsense.

fixed timer bug in calibrate encoder, in main

defined a label for serialusb, to make it easier to swap out.

firmware/lib/currentsense/InlineCurrentSenseSync.h

@@ -0,0 +1,75 @@
+#ifndef INLINE_CS_SYNC_LIB_H
+#define INLINE_CS_SYNC_LIB_H
+
+#include "Arduino.h"
+#include "SimpleFOC.h"
+#include "common/foc_utils.h"
+#include "common/time_utils.h"
+#include "common/defaults.h"
+#include "common/base_classes/CurrentSense.h"
+#include "common/lowpass_filter.h"
+// #include "current_sense/hardware_api.h"
+#include "utils.h"
+
+
+class InlineCurrentSenseSync: public CurrentSense{
+  public:
+    /**
+      InlineCurrentSense class constructor
+      @param shunt_resistor shunt resistor value
+      @param gain current-sense op-amp gain
+      @param phA A phase adc pin
+      @param phB B phase adc pin
+      @param phC C phase adc pin (optional)
+    */
+    InlineCurrentSenseSync(float shunt_resistor, float gain, int pinA, int pinB, int pinC = NOT_SET);
+    /**
+      InlineCurrentSense class constructor
+      @param mVpA mV per Amp ratio
+      @param phA A phase adc pin
+      @param phB B phase adc pin
+      @param phC C phase adc pin (optional)
+    */
+    InlineCurrentSenseSync(float mVpA, int pinA, int pinB, int pinC = NOT_SET);
+
+    // CurrentSense interface implementing functions 
+    int init() override;
+    PhaseCurrent_s getPhaseCurrents() override;
+    int driverAlign(float align_voltage) override;
+
+    // ADC measuremnet gain for each phase
+    // support for different gains for different phases of more commonly - inverted phase currents
+    // this should be automated later
+    float gain_a; //!< phase A gain
+    float gain_b; //!< phase B gain
+    float gain_c; //!< phase C gain
+
+    // // per phase low pass fileters
+    // LowPassFilter lpf_a{DEF_LPF_PER_PHASE_CURRENT_SENSE_Tf}; //!<  current A low pass filter
+    // LowPassFilter lpf_b{DEF_LPF_PER_PHASE_CURRENT_SENSE_Tf}; //!<  current B low pass filter
+    // LowPassFilter lpf_c{DEF_LPF_PER_PHASE_CURRENT_SENSE_Tf}; //!<  current C low pass filter
+
+    float offset_ia; //!< zero current A voltage value (center of the adc reading)
+    float offset_ib; //!< zero current B voltage value (center of the adc reading)
+    float offset_ic; //!< zero current C voltage value (center of the adc reading)
+    
+  private:
+  
+    // hardware variables
+  	int pinA; //!< pin A analog pin for current measurement
+  	int pinB; //!< pin B analog pin for current measurement
+  	int pinC; //!< pin C analog pin for current measurement
+
+    // gain variables
+    float shunt_resistor; //!< Shunt resistor value
+    float amp_gain; //!< amp gain value
+    float volts_to_amps_ratio; //!< Volts to amps ratio
+    
+    /**
+     *  Function finding zero offsets of the ADC
+     */
+    void calibrateOffsets();
+
+};
+
+#endif