An Arduino-compatible C++ library for controlling all peripherals on the Pico4Drive development board.

Pico4Drive is designed for small robotics and high-current control applications, combining motor drivers, power management, expanded analog inputs, and safe voltage interfacing in a single board based on the Raspberry Pi Pico.

This library exposes a API matching the Pico4Drive hardware, allowing control of motors, power management, and analog inputs.

• DC Motor Control

  • Up to 4 brushed DC motors
  • Up to 2A continuous (4A peak) per motor
  • High-resolution PWM (10-bit)
  • Voltage-based or raw PWM control

• Power Management (using the AVR Tiny Controller)

  • Software-controlled power-off
  • Battery voltage monitoring
  • ON button state and press counting
  • Ultra-low power off state (~3 µA total board consumption)

• Analog Inputs

  • 10 total analog inputs
    • 2 direct Pico ADC inputs
    • 8 multiplexed inputs
  • multiplexed ADC read function

• 5V Power Support

  • On-board 5V switching regulator (1A)
  • Safe interfacing with 5V (and up to 12V) signals via two sets of resistor dividers

• GPIO Access

  • All 13 header GPIO pins are free for user applications
  • Some Pico pins are reserved for board functions

• Pico4Drive board
• Raspberry Pi Pico / Pico W
• Arduino-Pico core (Earle Philhower or compatible)

1. Open Arduino IDE
2. Sketch → Include Library → Manage Libraries…
3. Search for "Pico4Drive"
4. Install the latest version

1. Download or clone this repository
2. Copy the folder into your Arduino libraries directory
3. Restart the Arduino IDE

Motors are identified using the driver_num_t enum:

typedef enum {
  p2d_drv1 = 0,
  p2d_drv2,
  p2d_drv3,
  p2d_drv4
} driver_num_t;

#include <Pico4Drive.h>

pico4drive_t pico4drive;

void setup() {
    pico4drive.init();          // Default PWM frequency: 16 kHz
}

You may optionally specify a custom PWM frequency:

pico4drive.init(20000);         // 20 kHz PWM

• PWM resolution is 10 bits

• Maximum PWM value:

  pico4drive.analogWriteMax // 1023

• The library internally limits PWM using:

  pico4drive.PWM_limit;

This value can be adjusted by user code to restrict the maximum motor voltage. By default, it is set to produce approximately 5.5 V output from a 7.4 V supply (2 × Li-Ion cells).

Set motor PWM directly (positive or negative values control direction):

pico4drive.set_driver_PWM(400, p2d_drv1);
pico4drive.set_driver_PWM(-600, p2d_drv2);

Set motor output based on a desired voltage:

pico4drive.set_driver_voltage(4.5, p2d_drv3);

The voltage is internally converted to PWM using the measured current battery voltage.

Reads multiplexed analog inputs:

uint16_t value = pico4drive.read_adc(0);

The following fields are updated by calling update():

pico4drive.battery_voltage;
pico4drive.button_state;
pico4drive.button_press_count;

Example:

void loop() {
    pico4drive.update();

    if (pico4drive.button_state) {
        // Button currently pressed
    }
}

button_press_count can be reset by user code as needed.

Requests the AVR Tiny controller to shut down the board:

pico4drive.power_off();

This places the board into its ultra-low-power sleep state.

void loop() {
    pico4drive.update();

    // Application logic here
}

Calling update() regularly ensures battery voltage and button state remain current.

• Constructor:

  • pico4drive_t()

• Initialization:

  • init(PWM_freq = 16000)

• Motor control:

  • set_driver_PWM(new_PWM, driver_num)
  • set_driver_voltage(new_voltage, driver_num)
  • voltage_to_PWM(voltage)

• Analog input:

  • read_adc(channel)

• Power management:

  • power_off()

• State update:

  • update()

• Public state variables:

  • battery_voltage
  • button_state
  • button_press_count
  • PWM_limit
  • analogWriteBits
  • analogWriteMax

• GPIOs used internally for:
  • Motor drivers
  • Analog multiplexer
  • AVR Tiny communication are not exposed on the headers.
• All 13 header GPIO pins connect directly to the Pico.
• AVR Tiny communication uses a single Pico GPIO pin.

BSD 2-Clause

Contributions, bug reports, and feature requests are welcome. Please open an issue or submit a pull request.