Power Pins

  • GND - this is the power and signal ground pin
  • Vin - this is the power pin, connect to 3-5VDC - it has reverse polarity protection but try to wire it right!
  • 3Vo - this is the 3.3V output from the onboard regulator, you can 'borrow' about 100mA if you need to power some other 3.3V logic devices

StemmaQT Ports

The display comes with 2 StemmaQT ports. Normally you would use one for an input and one for an output in order to chain multiple StemmaQT devices. Since they are connected in parallel, either side can be used as an input or output.

I2C and SPI Jumpers

The Stemma QT ports will only work when the display is in I2C Mode.

You'll notice there are a few solderable jumpers on the back. To use in I2C mode, you'll want to make sure the J1 and J2 are bridged. To use in SPI mode, you'll want to cut the traces between the jumpers for both J1 and J2. The board comes in I2C mode by default.

The A0 jumper is used for setting the I2C address. When it is open, the I2C address is 0x3D. When it is bridged, the I2C Address is 0x3C. Alternatively, by tying the A0 pin to ground, you can set the I2C address to 0x3C.

I2C Pins

  • Rst - this is the Reset pin. You may be able to share this with your microcontroller reset pin but, if you can, connect it to a digital pin.
  • Clk - this is the Clock pin and is connected to I2C SCL
  • Data - this is the Data pin and is connected to I2C SDA

SPI Pins

  • CS - this is the Chip Select pin, it is used by SPI to select the device.
  • Rst - this is the Reset pin, you may be able to share this with your microcontroller reset pin but if you can, connect it to a digital pin.
  • DC - this is the Data/Command selector pin used to differentiate between Data and Commands that are sent to the display.
  • Clk - this is the Clock pin and is connected to SPI SCLK
  • Data - this is the Data pin and is connected to SPI MOSI

This guide was first published on Nov 10, 2020. It was last updated on Nov 10, 2020.

This page (Pinouts) was last updated on Nov 10, 2020.