Speed up screen redraws with a BeagleBone Black and Adafruit TFT #BeagleBoneBlack @TXInstruments @BeagleBoardOrg
Speed up screen redraws with a BeagleBone Black and Adafruit TFT via Matthew McMillan
In a previous post I wrote about experimenting with the BeagleBone Black and an Adafruit 2.2″ TFT screen. The TFT screen communicates over SPI using a userspace library. Being a userspace library it is expected it will be slower than driver that is compiled into the kernel but something in the code seemed to be causing redraws to be unnecessarily slow.
To measure how long the screen draws were taking I modified the example image.py script to read the time right before and right after the screen draw function call. I also wrapped a while loop around it so it would redraw the screen repeatedly to give me an average of how long it took.
Depending on how much of the screen was being redrawn and the load on the BBB it would take between 0.7 seconds to 0.9 seconds to execute the disp.display(image) function.
One of the commenters on my previous post tracked down the slowness to one specific function named ‘image_to_data’ in the file ILI9341.py. He also supplied a modification that reduced his screen redraw time dramatically by using NumPy. I tried it out and it reduced my screen redraw times dramatically. Screen redraws went from 0.85 seconds to 0.17 seconds. That is an 80% improvement!
Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.