Back to Home11/9/2025, 12:03:47 AM

Driving TFEL with RP2040: Offloading the CPU step by step (2021)

starkparker
25 points
9 comments

Mood

thoughtful

Sentiment

positive

Category

tech

Key topics

RP2040

TFEL

Microcontrollers

Embedded Systems

Debate intensity20/100

The post explores offloading CPU tasks to drive a Thin-Film Electroluminescent (TFEL) display using an RP2040 microcontroller, showcasing a step-by-step process.

Snapshot generated from the HN discussion

Discussion Activity

Moderate engagement

First comment

7d

Peak period

6

Day 7

Avg / period

6

Comment distribution6 data points

Based on 6 loaded comments

Key moments

  1. 01Story posted

    11/9/2025, 12:03:47 AM

    10d ago

    Step 01
  2. 02First comment

    11/15/2025, 2:00:46 PM

    7d after posting

    Step 02
  3. 03Peak activity

    6 comments in Day 7

    Hottest window of the conversation

    Step 03
  4. 04Latest activity

    11/15/2025, 4:39:30 PM

    3d ago

    Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (9 comments)
Showing 6 comments of 9
marcosscriven
3d ago
1 reply
Always impressed with the PIO capabilities.

Reminds me of the old BeagleBone Black that had two small separate cores that worked in a similar way. Someone used it to create a 3D printer control system.

Are there any other chips out there like this?

bri3d
3d ago
1 reply
Application / realtime split cores are very common, STM32MP* was designed around the application processor / realtime processor split, I don’t remember if that’s what was on that Beaglebone. Any “big” application processor these days will have a variety of smaller generic cores (Cortex-M style) around it, some which usually handle programmable I/O.

A lot of microcontrollers also have pretty sophisticated interrupt controllers and timing analyzers which can be used to accomplish similar tasks, although they’re usually “programmed” by chaining register effects so it’s nowhere near as elegant as PIO.

Specialized IO coprocessors which are programmed using “code” like PIO is are a little less common, Infineon Peripheral Control Processor springs to mind.

marcosscriven
3d ago
1 reply
I just refreshed my memory - they were called Programmable Realtime Units on this chip: https://uk.rs-online.com/web/p/microprocessors/1219716

Can the “little” cores in big.little arches be run entirely independently then? That’s pretty cool if so.

bri3d
3d ago
> Can the “little” cores in big.little arches be run entirely independently then?

Well, that too :) What I’m referring to is more like Qualcomm “safety island” on Dragonwing, Xilinx RPU, or Allwinner AR100 (I think this is used in 3D printer projects using A64, actually), though - where most modern large “embedded” Linux SoCs have some real time island to talk to the outside world. Cell phone SoCs and stuff like Apple M also have realtime cores hiding in them running blobs, although they’re usually connected to more specific RF or A/V blocks rather than generic IO.

deivid
3d ago
These screens look amazing, but $1500-2500 is a bit much. Any other screens with this monichrome CRT style?
mmastrac
3d ago
Ooh. I've been putting together a VT420 emulator and I am trying to figure out the best way to build one from scratch. I will probably end up building an RP2040 version of the video controller.

These look great, but I wonder if there's an 800x420ish version out there.

3 more comments available on Hacker News

View full discussion on Hacker News
ID: 45861463Type: storyLast synced: 11/16/2025, 9:42:57 PM

Want the full context?

Jump to the original sources

Read the primary article or dive into the live Hacker News thread when you're ready.

Read ArticleView on HN