Pico_BusIO

Pico_BusIO is a standalone port of the Arduino Wire and SPI interfaces for the RP2040, designed specifically to support Adafruit_BusIO-based sensor libraries in native pico-sdk CMake projects.
It allows Adafruit sensor drivers to be used on the Raspberry Pi Pico without the Arduino framework, platform files, or the Arduino build system.

This project was adapted from the Wire and SPI implementations in Arduino-Pico, refactored and simplified for direct integration in non-Arduino environments.

---

Example: Reading from a BMP388 / BMP390

#include "Adafruit_BMP3XX.h"
#include "Wire.h"
#include "pico/stdlib.h"

#define I2C_BLOCK i2c0
#define PIN_SDA 16
#define PIN_SCL 17
#define SEALEVELPRESSURE_HPA (1013.25)

int main() {
  stdio_init_all();
  while(!stdio_usb_connected())
    sleep_ms(100);

  printf("Adafruit BMP388 / BMP390 test\n");

  Adafruit_BMP3XX bmp;
  TwoWire i2c(I2C_BLOCK, PIN_SDA, PIN_SCL);
  i2c.begin();

  if (!bmp.begin_I2C(0x77, &i2c)) {
    printf("Could not find a valid BMP3 sensor\n");
    while(1);
  }

  bmp.setTemperatureOversampling(BMP3_OVERSAMPLING_8X);
  bmp.setPressureOversampling(BMP3_OVERSAMPLING_4X);
  bmp.setIIRFilterCoeff(BMP3_IIR_FILTER_COEFF_3);
  bmp.setOutputDataRate(BMP3_ODR_50_HZ);

  while(1) {
    if (!bmp.performReading()) return 0;

    printf("Temperature = %.3f °C\n", bmp.temperature);
    printf("Pressure = %.3f hPa\n", bmp.pressure / 100.0);
    printf("Altitude = %.0f m\n", bmp.readAltitude(SEALEVELPRESSURE_HPA));

    sleep_ms(2000);
  }
}

CMake Integration

Add this repository as a subdirectory:

add_subdirectory(Pico_BusIO)

target_link_libraries(your_target
  PRIVATE
    pico_stdlib
    pico_busio
)

Licensing

This project contains code adapted from Arduino-Pico, originally released under the MIT License.
All original copyright notices are preserved.
Modifications for Pico_BusIO are also released under the MIT License.

See LICENSE for full details.