Sitron Labs Onsemi FUSB302 Arduino Library

Arduino library for interfacing with the Onsemi FUSB302 USB Type-C Port Controller.

Description

The FUSB302 is a programmable USB Type-C controller with USB Power Delivery support. It can detect USB Type-C cable orientation, measure VBUS voltage, and handle USB Power Delivery protocol communication. This library provides a simple interface to access these features via I2C, supporting both FUSB302B (default sink) and FUSB302T (default source) variants.

Installation

Arduino IDE

Install via the Arduino Library Manager by searching for "Sitron Labs FUSB302".

Alternatively, install manually:

1. Download or clone this repository
2. Place it in your Arduino libraries folder
3. Restart the Arduino IDE

PlatformIO

Install via the PlatformIO Library Manager by searching for "Sitron Labs FUSB302".

Alternatively, add the library manually to your platformio.ini file:

lib_deps = 
    https://github.com/sitronlabs/SitronLabs_Onsemi_FUSB302_Arduino_Library.git

Hardware Connections

Connect the FUSB302 to your Arduino using I2C:

• VDD → 3.3V or 5.0V
• GND → GND
• SDA → SDA (I2C Data, requires 4.7kΩ pull-up to VDD)
• SCL → SCL (I2C Clock, requires 4.7kΩ pull-up to VDD)
• CC1 → USB Type-C connector CC1 pin
• CC2 → USB Type-C connector CC2 pin
• VBUS → USB Type-C connector VBUS pin (up to 20V)
• INT → Any digital pin (optional, for interrupts)

Important Notes:

• The FUSB302 can operate at 3.3V or 5.0V. I2C pull-up resistors should be connected to the same voltage as VDD.
• I2C lines require 4.7kΩ pull-up resistors to VDD.
• The default I2C address is 0x22 (FUSB302BMPX) or 0x22/0x23 (FUSB302TMPX, configurable).

Usage

Basic Cable Detection

#include <Wire.h>
#include <fusb302.h>

// Create FUSB302 device object
fusb302 usb_controller;

// I2C address (typically 0x22)
const uint8_t I2C_ADDRESS = 0x22;

void setup() {
  Serial.begin(115200);
  
  // Initialize I2C
  Wire.begin();
  
  // Setup the FUSB302 (I2C library, I2C address)
  if (usb_controller.setup(Wire, I2C_ADDRESS) != 0) {
    Serial.println("Failed to setup FUSB302");
    return;
  }
  
  // Detect the device
  if (!usb_controller.detect()) {
    Serial.println("FUSB302 not detected");
    return;
  }
  
  // Power on the device
  usb_controller.power_set(true);
  
  // Configure CC pins as pull-down (for acting as device/sink)
  usb_controller.cc_pull_down();
  
  Serial.println("FUSB302 initialized");
}

void loop() {
  // Measure CC pins to detect cable orientation
  enum usb_typec_cc_status cc1, cc2;
  if (usb_controller.cc_measure(cc1, cc2) == 0) {
    if (cc1 > USB_TYPEC_CC_STATUS_OPEN && cc2 == USB_TYPEC_CC_STATUS_OPEN) {
      Serial.println("Cable: Normal orientation");
      usb_controller.cc_orientation_set(USB_TYPEC_CC_ORIENTATION_NORMAL);
    } else if (cc1 == USB_TYPEC_CC_STATUS_OPEN && cc2 > USB_TYPEC_CC_STATUS_OPEN) {
      Serial.println("Cable: Flipped orientation");
      usb_controller.cc_orientation_set(USB_TYPEC_CC_ORIENTATION_REVERSE);
    } else {
      Serial.println("No cable detected");
    }
  }
  
  delay(1000);
}

VBUS Voltage Monitoring

void loop() {
  float voltage;
  if (usb_controller.vbus_measure(voltage) == 0) {
    Serial.print("VBUS: ");
    Serial.print(voltage, 2);
    Serial.println(" V");
  }
  delay(1000);
}

USB Power Delivery Communication

#include <Wire.h>
#include <fusb302.h>
#include <usb_pd.h>

fusb302 usb_controller;
const uint8_t I2C_ADDRESS = 0x22;

void setup() {
  Serial.begin(115200);
  Wire.begin();
  
  usb_controller.setup(Wire, I2C_ADDRESS);
  usb_controller.detect();
  usb_controller.power_set(true);
  usb_controller.cc_pull_down();
  
  // Initialize Power Delivery
  usb_controller.pd_reset_logic();
  usb_controller.pd_autogoodcrc_set(true);
  usb_controller.pd_autoretry_set(3);
  usb_controller.pd_rx_flush();
  
  Serial.println("PD initialized");
}

void loop() {
  // Check for received PD messages
  struct usb_pd_message msg;
  int result = usb_controller.pd_message_receive(msg);
  
  if (result == 1) {
    Serial.print("Received PD message: Header=0x");
    Serial.println(msg.header, HEX);
    // Process message...
  } else if (result < 0) {
    Serial.println("Error receiving message");
  }
  
  delay(100);
}

API Reference

setup(TwoWire &i2c_library, uint8_t i2c_address)

Initializes the FUSB302 device.

• i2c_library: I2C library instance to use (typically Wire)
• i2c_address: I2C address (typically 0x22)

Returns 0 on success, or a negative error code otherwise.

detect(void)

Detects if the FUSB302 device is present on the I2C bus by reading the device ID register.

Returns true if the device is detected, false otherwise.

reset(void)

Performs a software reset of the entire chip.

Returns 0 on success, or a negative error code otherwise.

power_set(bool on)

Controls the power state of the FUSB302 device.

• on: true to power on, false to power off

Returns 0 on success, or a negative error code otherwise.

cc_pull_down(void)

Configures the FUSB302 to present Rd (pull-down) resistors on both CC pins. Use this when acting as a device/sink.

Returns 0 on success, or a negative error code otherwise.

cc_pull_up(enum usb_typec_cc_status status)

Configures the FUSB302 to present Rp (pull-up) resistors on both CC pins. Use this when acting as a host/source.

• status: The current level to advertise (USB_TYPEC_CC_STATUS_RP_DEF, USB_TYPEC_CC_STATUS_RP_1_5, or USB_TYPEC_CC_STATUS_RP_3_0)

Returns 0 on success, or a negative error code otherwise.

cc_measure(enum usb_typec_cc_status &cc1, enum usb_typec_cc_status &cc2)

Measures the voltage levels on both CC pins to determine their status and detect cable orientation.

• cc1: Output parameter for CC1 pin status
• cc2: Output parameter for CC2 pin status

Returns 0 on success, or a negative error code otherwise.

cc_orientation_set(enum usb_typec_cc_orientation orientation)

Configures the FUSB302 for a specific USB Type-C cable orientation. Call this after detecting cable orientation.

• orientation: USB_TYPEC_CC_ORIENTATION_NORMAL or USB_TYPEC_CC_ORIENTATION_REVERSE

Returns 0 on success, or a negative error code otherwise.

vbus_measure(float &voltage)

Measures the VBUS voltage using the internal comparator and MDAC.

• voltage: Output parameter for the measured voltage in Volts

Returns 0 on success, or a negative error code otherwise.

pd_reset_logic(void)

Resets the USB Power Delivery logic of the FUSB302. Call this before starting PD communication.

Returns 0 on success, or a negative error code otherwise.

pd_reset_hard(void)

Sends a USB Power Delivery Hard Reset sequence.

Returns 0 on success, or a negative error code otherwise.

pd_autogoodcrc_set(bool enabled)

Enables or disables automatic GoodCRC response for received USB PD messages.

• enabled: true to enable automatic GoodCRC response, false to disable

Returns 0 on success, or a negative error code otherwise.

pd_autoretry_set(int retries)

Configures automatic retry behavior for USB PD message transmission.

• retries: Number of retry attempts (0-3)

Returns 0 on success, or a negative error code otherwise.

pd_rx_flush(void)

Flushes the USB PD receive FIFO buffer.

Returns 0 on success, or a negative error code otherwise.

pd_tx_flush(void)

Flushes the USB PD transmit FIFO buffer.

Returns 0 on success, or a negative error code otherwise.

pd_message_receive(struct usb_pd_message &msg)

Checks for and receives a USB Power Delivery message from the FUSB302.

• msg: Output parameter for the received message structure

Returns 1 if a message was successfully received, 0 if no message was available, or a negative error code otherwise.

pd_message_send(const struct usb_pd_message msg)

Sends a USB Power Delivery message through the FUSB302.

• msg: The message structure to send

Returns 0 on success, or a negative error code otherwise.

Message structure:

struct usb_pd_message {
    enum usb_pd_sop_type sop_type;  // SOP, SOP', or SOP''
    uint16_t header;                 // Message header
    uint32_t objects[7];             // Data objects
    uint8_t object_count;            // Number of objects (0-7)
};

register_read(enum fusb302_register address, uint8_t *content, size_t count = 1)

Low-level register read operation (advanced usage).

• address: Register address to read from
• content: Pointer to buffer where read data will be stored
• count: Number of registers to read (default: 1)

Returns 0 on success, or a negative error code otherwise.

register_write(enum fusb302_register address, const uint8_t *content, size_t count = 1)

Low-level register write operation (advanced usage).

• address: Register address to write to
• content: Pointer to buffer containing data to write
• count: Number of registers to write (default: 1)

Returns 0 on success, or a negative error code otherwise.

Specifications

• Supported devices: FUSB302B (default sink), FUSB302T (default source)
• Communication interface: I2C
• I2C address: 0x22 (FUSB302BMPX) or 0x22/0x23 (FUSB302TMPX, configurable)
• Operating voltage: 3.3V or 5.0V
• VBUS measurement range: 0-22V
• USB Power Delivery: Full support for PD protocol
• SOP types: SOP, SOP', and SOP''
• CC pin configuration: Pull-up (Rp) or pull-down (Rd) resistors