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Interface 0.96″ OLED Display with Raspberry Pi Pico

Introduction

In this tutorial we will learn how to Interface 0.96″ OLED Display with Raspberry Pi Pico Board, The OLED display is the one of the most popular and Attractive Display available for a microcontrollers.

The organic light-emitting diode (OLED) display that we’ll use in this tutorial is the SSD1306 model Display With Raspberry Pi Pico 0.96-inch display with 128×64 pixels.

Required Components

SSD1306 Module

Basically the SSD1306 does communicate with the microcontroller to get the data and send it to the OLED screen to draw that data, Communication between the SSD1306 and the microcontroller, be it an Raspberry Pi Pico or an Arduino, is done via SPI or I2C .

  • Generally, SPI communication is faster than I2C communication .
  • In contrast, SPI communication requires more pins than I2C communication .

OLED screens have the advantage of having a very low consumption , around 20mA, since only the necessary pixel is lit and they do not require a backlight. This is especially interesting in battery-powered applications.

SSD1306 Pinout 

  • GND : ground pin.
  • VCC : is the power pin. The screen can be powered between 1.8V and 6V.
  • SCL : is the clock signal pin of the I2C interface.
  • SDA : It is the data signal pin of the I2C interface.

OLED Display with Raspberry Pi Pico Schematics

OLED Display with Raspberry Pi Picowiring is very simple. You just need to connect to the Raspberry Pi pico I2C pins as shown in the Below

OLED Pin Wiring to Raspberry Pi pico
Vin 3.3V
GND GND
SCL GP9
SDA GP8

Source Code and Libraries

To control the OLED display with Micropython code you need the OLED libraries. Follow the next instructions to install those libraries.

The programming here is divided into two main parts:

1. SSD1306.py // this is SSD1306 Driver Code
2. Main.py   
  //  this is main code

SSD1306.py

Firstly you need to  create a new file in Thonny IDE. Copy the following code & save the file by the name ssd1306.py in Raspberry Pi Pico Board.

from micropython import const
import framebuf


# register definitions
SET_CONTRAST = const(0x81)
SET_ENTIRE_ON = const(0xA4)
SET_NORM_INV = const(0xA6)
SET_DISP = const(0xAE)
SET_MEM_ADDR = const(0x20)
SET_COL_ADDR = const(0x21)
SET_PAGE_ADDR = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP = const(0xA0)
SET_MUX_RATIO = const(0xA8)
SET_COM_OUT_DIR = const(0xC0)
SET_DISP_OFFSET = const(0xD3)
SET_COM_PIN_CFG = const(0xDA)
SET_DISP_CLK_DIV = const(0xD5)
SET_PRECHARGE = const(0xD9)
SET_VCOM_DESEL = const(0xDB)
SET_CHARGE_PUMP = const(0x8D)

# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
    def __init__(self, width, height, external_vcc):
        self.width = width
        self.height = height
        self.external_vcc = external_vcc
        self.pages = self.height // 8
        self.buffer = bytearray(self.pages * self.width)
        super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
        self.init_display()

    def init_display(self):
        for cmd in (
            SET_DISP | 0x00,  # off
            # address setting
            SET_MEM_ADDR,
            0x00,  # horizontal
            # resolution and layout
            SET_DISP_START_LINE | 0x00,
            SET_SEG_REMAP | 0x01,  # column addr 127 mapped to SEG0
            SET_MUX_RATIO,
            self.height - 1,
            SET_COM_OUT_DIR | 0x08,  # scan from COM[N] to COM0
            SET_DISP_OFFSET,
            0x00,
            SET_COM_PIN_CFG,
            0x02 if self.width > 2 * self.height else 0x12,
            # timing and driving scheme
            SET_DISP_CLK_DIV,
            0x80,
            SET_PRECHARGE,
            0x22 if self.external_vcc else 0xF1,
            SET_VCOM_DESEL,
            0x30,  # 0.83*Vcc
            # display
            SET_CONTRAST,
            0xFF,  # maximum
            SET_ENTIRE_ON,  # output follows RAM contents
            SET_NORM_INV,  # not inverted
            # charge pump
            SET_CHARGE_PUMP,
            0x10 if self.external_vcc else 0x14,
            SET_DISP | 0x01,
        ):  # on
            self.write_cmd(cmd)
        self.fill(0)
        self.show()

    def poweroff(self):
        self.write_cmd(SET_DISP | 0x00)

    def poweron(self):
        self.write_cmd(SET_DISP | 0x01)

    def contrast(self, contrast):
        self.write_cmd(SET_CONTRAST)
        self.write_cmd(contrast)

    def invert(self, invert):
        self.write_cmd(SET_NORM_INV | (invert & 1))

    def show(self):
        x0 = 0
        x1 = self.width - 1
        if self.width == 64:
            # displays with width of 64 pixels are shifted by 32
            x0 += 32
            x1 += 32
        self.write_cmd(SET_COL_ADDR)
        self.write_cmd(x0)
        self.write_cmd(x1)
        self.write_cmd(SET_PAGE_ADDR)
        self.write_cmd(0)
        self.write_cmd(self.pages - 1)
        self.write_data(self.buffer)


class SSD1306_I2C(SSD1306):
    def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):
        self.i2c = i2c
        self.addr = addr
        self.temp = bytearray(2)
        self.write_list = [b"\x40", None]  # Co=0, D/C#=1
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.temp[0] = 0x80  # Co=1, D/C#=0
        self.temp[1] = cmd
        self.i2c.writeto(self.addr, self.temp)

    def write_data(self, buf):
        self.write_list[1] = buf
        self.i2c.writevto(self.addr, self.write_list)


class SSD1306_SPI(SSD1306):
    def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
        self.rate = 10 * 1024 * 1024
        dc.init(dc.OUT, value=0)
        res.init(res.OUT, value=0)
        cs.init(cs.OUT, value=1)
        self.spi = spi
        self.dc = dc
        self.res = res
        self.cs = cs
        import time

        self.res(1)
        time.sleep_ms(1)
        self.res(0)
        time.sleep_ms(10)
        self.res(1)
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs(1)
        self.dc(0)
        self.cs(0)
        self.spi.write(bytearray([cmd]))
        self.cs(1)

    def write_data(self, buf):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs(1)
        self.dc(1)
        self.cs(0)
        self.spi.write(buf)
        self.cs(1)

Open a new tab again in the Thonny IDE. Copy the following below code and paste it on the Thonny IDE new tab. Save the file by the name main.py in Raspberry Pi Pico.

import machine
import ssd1306
import time

oled = ssd1306.SSD1306_I2C(128, 64, machine.I2C(0))

oled.text("Hello everyone", 0, 0)
oled.show()
time.sleep(2)
oled.text("Welcome to my", 0, 10)
oled.text("channel", 0, 20)
oled.show()
time.sleep(2)
oled.text("Thank You", 0, 30)
oled.show()

Conclusion

After Upload code You will see that the OLED Start Texting on Display.

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