We will demonstrate using this display with an Arduino UNO compatible. If you are using a 3V logic device you can skip the level shifter and connect direct from the microcontroller to display. You can also use another kind of level shifter if you like.
Any microcontroller with I2C + 1 pin or 4 or 5 pins can be used, but we recommend testing it out with an UNO before you try a different processor.
Since this is a SPI-capable display, we can use hardware or 'software' SPI. To make wiring identical on all Arduinos, we'll begin with 'software' SPI. The following pins should be used:
- Connect Pin #1 to common power/data ground line (black wires)
- Connect Pin #2 to the 3V power supply on your Arduino. (red wires)
- Skip pin #3
- Connect Pin #4 (DC) to digital #8 via the level shifter (white wires) any pin can be used later
- Connect Pin #7 (SCLK) to digital #13 via the level shifter (blue wires) any pin can be used later
- Connect Pin #8 (DIN) to digital #11 via the level shifter (green wires) any pin can be used later
- Skip pins #9-14
- Connect Pin #15 (CS) to digital #10 via the level shifter (yellow wires) any pin can be used later
- Connect Pin #16 (RST) to digital #9 via the level shifter (orange wires) any pin can be used later
Later on, once we get it working, we can adjust the library to use hardware SPI if you desire, or change the pins to any others.
Level Shifter Wiring
You will also want to power the HC4050 level shifter by connecting pin #1 to 3V (the red wire) and pin #8 to ground (the black wire)
3.3V Capacitor
We also include a 220uF capacitor with your order because we noticed that the 3V line can fluctuate a lot when powered via an Arduino's 3.3V regulator. We really recommend installing it. Clip the leads on this capacitor and connect the negatve pin to GND and the positive pin to 3V
Download Libraries
To begin reading sensor data, you will need to download Adafruit_SSD1305 and Adafruit_GFX. You can install these libraries via the Arduino library manager.
Open up the Arduino library manager:
Search for the Adafruit GFX library and install it:
If using an older (pre-1.8.10) Arduino IDE, locate and install Adafruit_BusIO (newer versions do this one automatically).
Then, search for the Adafruit SSD1305 library and install it
We also have a great tutorial on Arduino library installation at: http://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use
Running the Demo
After restarting the Arduino software, you should see a new example folder called Adafruit_SSD1305 and inside, an example called ssd1305test
Now upload the sketch to your Arduino. That's pretty much it! You should see immediate update of the display.
If nothing shows up at all, make sure you have your wiring correct, we have a diagram above you can use. Also, check that you converted the module to "SPI" mode (see the Assembly) step on how to do that
Adjust display size
The display size, in terms of width and height, is specified as the first two parameters passed in when creating the display instance. For example, for a display with width=128 and height=64:
Adafruit_SSD1305 display(128, 64, ...
Change these as needed for the display size being used.
Changing Pins
Now that you have it working, there's a few things you can do to change around the pins.
If you're using Hardware SPI, the CLOCK and MOSI pins are 'fixed' and cant be changed. But you can change to software SPI, which is a bit slower, and that lets you pick any pins you like. Find these lines:
// If using software SPI, define CLK and MOSI
#define OLED_CLK 13
#define OLED_MOSI 11
// These are neede for both hardware & softare SPI
#define OLED_CS 10
#define OLED_RESET 9
#define OLED_DC 8
Change those to whatever you like!
Using Hardware SPI
If you want a little more speed, you can 'upgrade' to Hardware SPI. Its a bit faster, maybe 2x faster to draw but requires you to use the hardware SPI pins.
- SPI CLK connects to SPI clock. On Arduino Uno/Duemilanove/328-based, thats Digital 13. On Mega's, its Digital 52 and on Leonardo/Due its ICSP-3 (See SPI Connections for more details)
- SPI DATA IN connects to SPI MOSI. On Arduino Uno/Duemilanove/328-based, thats Digital 11. On Mega's, its Digital 51 and on Leonardo/Due its ICSP-4 (See SPI Connections for more details)
To enable hardware SPI, look for these lines:
// software SPI //Adafruit_SSD1305 display(128, 64, OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS); // hardware SPI - use 7Mhz (7000000UL) or lower because the screen is rated for 4MHz, or it will remain blank! Adafruit_SSD1305 display(128, 64, &SPI, OLED_DC, OLED_RESET, OLED_CS, 7000000UL);
Make sure the software SPI line is commented out and the hardware SPI line is uncommented.
I2C Wiring
It is also possible to use the display in I2C mode. Its a little slower but uses way fewer pins.
For I2C you will need to use the hardware I2C pins on your Arduino or microcontroller. The following pins should be used:
- Connect Pin #1 to common power/data ground line (black wires)
- Connect Pin #2 to the 3V power supply on your Arduino. (red wires)
- Skip pin #3
- Connect Pin #4 (DC & I2C Addr0) to ground (black wire) to set the I2C address to 0x3C. If this is tied to 3.3V, it will set the I2C address to 0x3D
- Connect Pin #7 (SCL) to Arduino SCL (green wire)
- Connect 10K resistor from SCL to 3.3V
- Connect Pin #8 (SDA) to Arduino SDA (blue wire)
- Connect 10K resistor from SDA to 3.3V
- Connect Pin #9 (SDA2) to Pin #8 (small blue wire)
- Skip pins #9-15
- Connect Pin #16 (RST) to digital #9 by using a resistive divider as shown, two resistors from 1K to 10K both the same value can be used. Any pin can be used later
While its ideal to use level shifters on the I2C pins, you can sorta get away with this on an arduino, because the I2C pins are open collector and there are very weak pullups on those two lines. If using with other I2C devices, we suggest using a 3V-logic arduino or an I2C-safe shifter.
Later on, once we get it working, we can adjust the library to use hardware SPI if you desire, or change the pins to any others.
3.3V Capacitor
We also include a 220uF capacitor with your order because we noticed that the 3V line can fluctuate a lot when powered via an Arduino's 3.3V regulator. We really recommend installing it. Clip the leads on this capacitor and connect the negatve pin to GND and the positive pin to 3V
I2C code changes
In the test code, change the top area where you define the protocol used by commenting out the software and hardware SPI and uncommenting the I2C version
// software SPI //Adafruit_SSD1305 display(128, 64, OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS); // hardware SPI - use 7Mhz (7000000UL) or lower because the screen is rated for 4MHz, or it will remain blank! //Adafruit_SSD1305 display(128, 64, &SPI, OLED_DC, OLED_RESET, OLED_CS, 7000000UL); // I2C Adafruit_SSD1305 display(128, 64, &Wire, OLED_RESET);
Everything else about the display is identical to SPI mode.
By default we use I2C address 0x3C which is what we get by connecting DC/A0 to ground. If you tie that pin to 3.3V instead, the address will be 0x3D and all you have to do is call display.begin(0x3D) to initialize with that address.
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