# Dual BTS7960 Motor Driver Integration Plan

## Overview
Add a second BTS7960 motor driver for differential drive robot, sharing enable pins between both drivers.

## Hardware Configuration

### Pin Assignments

| Function | Motor 1 | Motor 2 | Notes |
|----------|---------|---------|-------|
| **R_EN** | GPIO 27 | GPIO 27 (shared) | Both drivers enable together |
| **L_EN** | GPIO 14 | GPIO 14 (shared) | Both drivers enable together |
| **RPWM** | GPIO 25 | GPIO 32 | Forward PWM |
| **LPWM** | GPIO 26 | GPIO 33 | Reverse PWM |
| **R_IS** | GPIO 34 | GPIO 36 (VP) | Current sense - input only |
| **L_IS** | GPIO 35 | GPIO 39 (VN) | Current sense - input only |

### Wiring Diagram

```
ESP32 LOLIN32          BTS7960 #1         BTS7960 #2
--------------         ----------         ----------
GPIO 27 (R_EN) ------> R_EN -----------> R_EN
GPIO 14 (L_EN) ------> L_EN -----------> L_EN
GPIO 25 (RPWM) ------> RPWM
GPIO 26 (LPWM) ------> LPWM
GPIO 34 (R_IS) <------ R_IS
GPIO 35 (L_IS) <------ L_IS
GPIO 32 (RPWM2) --------------------> RPWM
GPIO 33 (LPWM2) --------------------> LPWM
GPIO 36 (R_IS2) <-------------------- R_IS
GPIO 39 (L_IS2) <-------------------- L_IS
```

## Code Changes

### 1. config.h - Add Motor 2 pin definitions

```cpp
// Motor 2 BTS7960 Pin Definitions
#define RPWM2_PIN 32    // Right PWM Motor 2
#define LPWM2_PIN 33    // Left PWM Motor 2
#define R_IS2_PIN 36    // Right Current Sense Motor 2
#define L_IS2_PIN 39    // Left Current Sense Motor 2

// Motor 2 PWM Channels
#define PWM_CHANNEL_R2 2
#define PWM_CHANNEL_L2 3
```

### 2. motor.h - Parameterized MotorController

```cpp
struct MotorPins {
    uint8_t rpwm;
    uint8_t lpwm;
    uint8_t r_is;
    uint8_t l_is;
    uint8_t pwm_channel_r;
    uint8_t pwm_channel_l;
};

class MotorController {
public:
    MotorController(const MotorPins& pins, const char* name);
    void begin();
    // ... existing methods unchanged
private:
    MotorPins _pins;
    const char* _name;
    // ... existing members
};

extern MotorController motor1;
extern MotorController motor2;
```

### 3. motor.cpp - Use parameterized pins

- Constructor stores pin config
- `begin()` uses `_pins.rpwm` instead of `RPWM_PIN`, etc.
- Serial output includes motor name for debugging

### 4. webserver.cpp - Dual motor API

New endpoints:
- `/motor1/speed`, `/motor1/direction`, `/motor1/stop`
- `/motor2/speed`, `/motor2/direction`, `/motor2/stop`
- `/status` - returns both motors data

Keep legacy endpoints mapping to motor1 for backwards compatibility.

### 5. main.cpp - Initialize both controllers

```cpp
void setup() {
    motor1.begin();
    motor1.setStallCallback(onMotor1Stall);
    motor2.begin();
    motor2.setStallCallback(onMotor2Stall);
    // ...
}

void loop() {
    handleWebServer();
    motor1.update();
    motor2.update();
    delay(1);
}
```

## Notes

- Enable pins are set HIGH once in motor1.begin - both drivers share them
- GPIO 36 and 39 are valid for ADC input - they are input-only pins
- GPIO 32 and 33 support both PWM and ADC, using them for PWM only
- Web UI will need expansion to show both motors - consider tabbed interface or side-by-side layout