I need to:

  • Output data to a 128x64 screen with ug8lib (via SPI)

  • Keep track of the position of a high-precision rotary encoder (1024p/r)

  • Send about 2 bytes of data up to 120 times per second via an nrf24l01+ board (via SPI)

  • List item

Would the 3V Pro Trinket board, running an ATMega328P at 12Mhz, be powerful enough for this? I was originally going to use a way more powerful STM32-based board for this project, but I'm having trouble making it work with my OLED screen, so am considering reusing an old Pro Trinket I've got lying around.

  • Presumably you'll handle the encoder with interrupts so consider pin choice carefully. You've not stated the required update rate for the display or the allowed timing jitter for that or the radio. 240 bytes exceeds the nRF packet buffer so it will require a lot of interaction - do you require 240 bytes transferred or only 240 bytes attempted to be sent? You may also end up tight on RAM. – Chris Stratton Jun 12 '18 at 17:33
  • Sorry, I wasn't very clear. I don't need to send 240bytes every second, but 2 bytes at a maximum of 120x per second. The display doesn't need to be updated too fast, but still about 20-40fps, and it doesn't need to be very precise. The radio however can't have much timing jitter at all. – user2950509 Jun 12 '18 at 17:40
  • You may need to just try it and see what difficulties you run into. If you don't make your code to Arduino-ish you can likely re-use some of it for a different target. Or try to get the STM32 working. It's unclear if you've yet put much thought into the unreliability of the radio link. – Chris Stratton Jun 12 '18 at 17:43
  • does the screen have an integrated buffer? if not, then maybe use a second trinket to handle the screen display – jsotola Jun 12 '18 at 18:22
  • You may be hitting a wall with SPI. I have a 16x4 SPI board driven by an ATMege328P and it is quite slow updating. However, I just purchased a TFT touchscreen 240x320 (amzn.to/2t27B5B) and I'm driving via ATMega328P and it is amazingly fast. However, it has 8 separate data lines (parallel). Check out the video I added to my amazon review and you'll see it can keep up with redraws. Good luck. – raddevus Jun 12 '18 at 18:36

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