There is a built-in microSD card slot into the breakout, and that may be used to load bitmap images! You will need a microSD card formatted FAT16 or FAT32 (they almost always are by default).

It's really easy to draw bitmaps! Start by downloading this image of ADABOT

adabot.bmp

Rename the image to adabot.bmp.

You will want to download and 2 more images as well. Download and save the image below as miniwoof.bmp.

miniwoof.bmp

Download and save the image below as wales.bmp.

wales.bmp

Copy all 3 images into the base directory of a microSD card and insert it into the microSD socket in the breakout. The contents of your SD card should look like this:

Two more wires are required to interface with the onboard SD card:

  • You'll need to connect up the SO pin to the SPI MISO line on your microcontroller. On Arduino Uno/Duemilanove/328-based, that's Digital 12. On a Mega, it's Digital 50 and on Leonardo/Due it's ICSP-1 (See SPI Connections for more details)
  • Also, the CCS or CC pin to Digital 4 on your Arduino as well. You can change this pin later, but stick with this for now.

You may want to try the SD library examples before continuing, especially one that lists all the files on the SD card

Open the File→examples→Adafruit ImageReader Library→BreakoutST7789 - 320x170 example:

Now upload the example sketch to the Arduino. You should see ADABOT appear! If you have any problems, check the serial console for any messages such as not being able to initialize the microSD card or not finding the image.

To make new bitmaps, make sure they are no bigger than the display size in pixels and save them in 24-bit BMP format! They must be in 24-bit format, even if they are not 24-bit color as that is the easiest format for the Arduino. You can rotate images using the setRotation() procedure

You can draw as many images as you want - don't forget the names must be less than 8 characters long. Just copy the BMP drawing routines below loop() and call

bmpDraw(bmpfilename, x, y);

For each bitmap.

They can be smaller than 320x170 and placed in any location on the screen.

This guide was first published on Mar 29, 2022. It was last updated on 2022-03-29 15:25:45 -0400.

This page (Drawing Bitmaps) was last updated on Apr 16, 2022.

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