DRV8234 DC Motor Driver Expander Firmware & Driver Library

Professional C/C++ firmware library for the Pan Robotics DRV8234 DC Motor Driver Expander Breakout Module based on the Texas Instruments DRV8234 / DRV8235 2-A Brushed DC Motor Driver IC with I2C Interface, Sensorless Ripple Counting, and Stall Detection.

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Key Hardware & Driver Features

• High Voltage & Current: Up to 38V VM motor supply and 2A peak drive current.
• 7-Bit I2C Interface: Configurable via 3-state address pins A1 and A0 (Default: 0x38 with onboard 2.2k pull-ups). Up to 9 devices on a single I2C bus.
• Dual Bridge Control Modes:
  • Hardware Mode (I2C_BC = 0): Standard MCU PWM / GPIO control via IN1 and IN2 pins.
  • Pure I2C Mode (I2C_BC = 1): Zero MCU PWM pins required; forward, reverse, braking, and duty cycle (0–100%) commanded directly over the 2-wire I2C bus.
• Sensorless Commutation Ripple Counting:
  • Integrated 16-bit hardware ripple accumulator (RC_CNT).
  • Target ripple count threshold and automatic Hi-Z brake on target reached.
  • Real-time estimated ripple speed feedback in rad/s.
• Hardware Stall Detection:
  • Programmable inrush time blanking (tINRUSH, 5 ms to 6.7 s).
  • Latch Hi-Z or continue driving response modes.
  • Open-drain nFAULT pin notification.
• Real-Time Telemetry:
  • Live motor terminal voltage monitoring ($0\text{ to }38\text{ V}$).
  • Live motor current monitoring ($0\text{ to }4\text{ A}$ across selectable gain ranges).
• Protection Circuits:
  • Overcurrent Protection (OCP) with configurable auto-retry / latch-off.
  • Thermal Shutdown (TSD) with auto-retry.
  • Overvoltage Protection (OVP) active low-side braking during regenerative deceleration.

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Connector Pinout (Expander Board)

Connector	Pin(s)	Net Name	Description
J1	1, 2	GND	Power Ground
J1	3, 4	VM	Motor Power Supply ($4.5\text{V} - 38\text{V}$)
J2	1, 2	NSLEEP	Active-Low Sleep Control (High = Run, Low = Sleep)
J2	3, 4	IN1 / EN	PWM Speed Input / Enable Pin
J2	5, 6	IN2 / PH	Direction Input / Phase Pin
J3	1, 2	IPROPI	Analog Current Sense Output (1.2k onboard shunt to GND)
J3	3, 4	RC_OUT	Open-Drain Commutation Ripple Pulse Output
J3	5, 6	NFAULT	Open-Drain Fault Interrupt Output (Active-Low)
J4	1, 2	A1	I2C Address Bit 1 (Pulled up to VCC_MCU via 2.2k)
J4	3, 4	A0	I2C Address Bit 0 (Pulled up to VCC_MCU via 2.2k)
J4	5, 6	SDA	I2C Serial Data (Pulled up to VCC_MCU via 2.2k)
J4	7, 8	SCL	I2C Serial Clock (Pulled up to VCC_MCU via 2.2k)
J5	1, 2	OUT1	Motor Terminal 1
J5	3, 4	OUT2	Motor Terminal 2
J6	1, 2	VCC_MCU	Logic Power Reference ($1.8\text{V} - 5.0\text{V}$)
J6	3, 4	GND	Logic Ground
J6	5, 6	+3V3 / VREF	Analog Reference Voltage Input for Current Regulation

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Directory Structure

Firmware/
├── include/
│   └── drv8234.h          # ISO C99 low-level register map & API
├── src/
│   ├── drv8234.c          # C Driver implementation
│   ├── DRV8234.h          # Arduino / C++ Class wrapper header
│   └── DRV8234.cpp        # Arduino / C++ Class wrapper implementation
├── examples/
│   ├── Basic_Motor_Control/
│   │   └── Basic_Motor_Control.ino
│   ├── I2C_Software_Bridge_Control/
│   │   └── I2C_Software_Bridge_Control.ino
│   ├── Ripple_Counting_Position/
│   │   └── Ripple_Counting_Position.ino
│   └── Stall_Detection_Diagnostics/
│       └── Stall_Detection_Diagnostics.ino
├── test/
│   └── test_drv8234.c     # Host validation & unit test suite
├── library.properties     # Arduino IDE package metadata
├── keywords.txt           # Arduino IDE syntax highlighting
└── README.md              # Documentation

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Quick Start (Arduino)

#include <Wire.h>
#include <DRV8234.h>

// Instantiate motor object on default I2C address (0x38)
DRV8234 motor(DRV8234_I2C_ADDR_DEFAULT);

void setup() {
    Serial.begin(115200);
    Wire.begin();

    if (!motor.begin(Wire)) {
        Serial.println("DRV8234 init failed!");
        while (1);
    }

    // Drive forward at 75% duty cycle
    motor.forward(75.0);
}

void loop() {
    drv8234_telemetry_t telem;
    if (motor.getTelemetry(telem)) {
        Serial.print("Voltage: "); Serial.print(telem.motor_voltage_v); Serial.print(" V | ");
        Serial.print("Current: "); Serial.print(telem.motor_current_a * 1000.0); Serial.println(" mA");
    }
    delay(250);
}

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Custom C HAL Integration (STM32, ESP-IDF, Raspberry Pi Pico)

For pure C environments, populate drv8234_hal_t with your platform's I2C and delay functions:

#include "drv8234.h"

int my_i2c_write(uint8_t dev_addr, uint8_t reg_addr, const uint8_t *data, size_t len) {
    // Platform-specific I2C write (e.g. HAL_I2C_Mem_Write)
    return 0;
}

int my_i2c_read(uint8_t dev_addr, uint8_t reg_addr, uint8_t *data, size_t len) {
    // Platform-specific I2C read (e.g. HAL_I2C_Mem_Read)
    return 0;
}

void my_delay_ms(uint32_t ms) {
    // Platform delay
}

drv8234_handle_t motor;
drv8234_hal_t hal = {
    .i2c_write = my_i2c_write,
    .i2c_read  = my_i2c_read,
    .delay_ms  = my_delay_ms
};

void motor_init(void) {
    drv8234_init(&motor, &hal, NULL);
    drv8234_set_duty_cycle(&motor, 60.0f);
    drv8234_set_motor_state(&motor, DRV8234_MOTOR_FORWARD);
}