Hello, trying to program the first Pi pico rp2040 with a 0.96 single color oled screen. The problem I'm having is there are a few i2c lines it shows on the board. I don't know which ones do I use for the oled screen. Can someone please help me out to figure out which one and which code should I use to make this work?
Joseph
If it's not marked on the board, use an I2C scanner to find out. I googled one for you.
Does the OLED screen connect to the pico through wires or plug in headers?
What is its part number?
@sonofcy Its been a while since I played around with i2c. When I got these pico boards in I didn't know which I2C I can use as a default i2c. I have tired the other pins and they did find them but not the default i2c pins. I tired GP4 and GP5 on the pin and it showed up as the default i2c pins. which I saw in one of the google search pages. So I have tried and got this as a result.
I2C Scanner
Scanning...
I2C device found at address 0x3C !
done
Thank you for the scanner. the old one I was using doesn't work. It works on my uncle and leonardo boards but not the pico boards.
@EmilyJane The scanner from @sonofcy help me to identify the i2c pins I needed it. Thank you.
So which pins are they?
@EmilyJane GP4 and GP5. Pins 6 and 7.
And in case someone finds this topic and wonders what OLED screen that was, why don't you post the Model and a picture?
@EmilyJane You are right my fault there. I did not post about the screen itself. It is a 0.96 white OLED screen. This is where I got mine from is Amazon in the USA.
https://www.amazon.com/ELEGOO-Display-Compact-Self-Luminous-Projects/dp/B0FSRQG23K
All data pins have I2C functionality.
Pins marked I2C0 correspond to Wire, and those marked I2C1 to Wire1.
The default physical pins on Pico for I2C0 (Wire) are 6 and 7, but keep in mind that you must reference the GPIOs (that is, 4 and 5 respectively).
For more information
the RPi RP2040 Pico default I2C and SPI pins are
SDA 4
SCL 5
MOSI: 19
MISO: 16
SCK: 18
SS: 17
however, you can use the Wire.setSDA() and Wire.setSCL() methods to aselect other pins
e.g. a BMP280 using SDA GPIO20 and SCL GPIO21
// Interfacing RPi pico RP2040 with BMP280 temperature and pressure sensor.
#include <Wire.h> // include Wire library, required for I2C devices
#include <Adafruit_Sensor.h> // include Adafruit sensor library
#include <Adafruit_BMP280.h> // include adafruit library for BMP280 sensor
// define device I2C address: 0x76 or 0x77 (0x77 is library default address)
#define BMP280_I2C_ADDRESS 0x76
// define I2C1 RP2040 pins for BMP280
#define SDA 20
#define SCL 21
Adafruit_BMP280 bmp280(&Wire1);
void setup() {
Serial.begin(115200);
delay(3000);
Serial.println(F("RPi pico RP2040 + BMP280"));
Wire1.setSDA(SDA); // setup SDA and SCL pins
Wire1.setSCL(SCL);
Wire1.begin();
if (!bmp280.begin(BMP280_I2C_ADDRESS)) {
Serial.println("Could not find a valid BMP280 sensor, check wiring!");
while (1)
;
}
Serial.println("Found BMP280 sensor!");
}
void loop() {
// get temperature, pressure and altitude from library
float temperature = bmp280.readTemperature(); // get temperature
float pressure = bmp280.readPressure(); // get pressure
float altitude_ = bmp280.readAltitude(1013.25); // get altitude (this should be adjusted to your local forecast)
// print data on the serial monitor software
// 1: print temperature
Serial.print("Temperature = ");
Serial.print(temperature);
Serial.println(" °C");
// 2: print pressure
Serial.print("Pressure = ");
Serial.print(pressure / 100);
Serial.println(" hPa");
// 3: print altitude
Serial.print("Approx Altitude = ");
Serial.print(altitude_);
Serial.println(" m");
Serial.println(); // start a new line
delay(2000); // wait 2 seconds
}
serial monitor output
RPi pico RP2040 + BMP280
Found BMP280 sensor!
Temperature = 24.33 °C
Pressure = 1001.57 hPa
Approx Altitude = 97.70 m
Temperature = 24.69 °C
Pressure = 1001.64 hPa
Approx Altitude = 97.10 m
Temperature = 24.71 °C
Pressure = 1001.62 hPa
Approx Altitude = 97.24 m
Temperature = 24.71 °C
Pressure = 1001.64 hPa
Approx Altitude = 97.10 m