Vectorscope/docs/badge_talk_2023/badge_2023.md

Supercon 2023: The Vectorscope Badge

Overview

The Badge

• What is It?

• How Does it Work?

• Can I Hack It?

Inspiration: Analog

{height=500px}

One Badge, Two Parts

• Vectorscope: 30 kHz "scope"

• Signal Generator: Driven by code

• X/Y outputs, X/Y inputs (0 V - 3 V)

Vectorscope

• Fake phosphor display

• "No User-Serviceable Parts Inside"

• AK4619 Codec chip (codec.py)

• ADC in, 16 frames of 1024 samples (16-bit X/Y)

• Insane DMA/PIO Machine (pixel_pusher.py)

• Twelve lines of user-space code (vectorscope.phosphor())

Signal Generator

• DAC out

• Limitations: 30 kHz, ringy filter, one CPU core

• X/Y buffers, 256 points @ 16 bits, interleaved and pushed out

• This is your playground (waveform.py)

Signal Generator "API"

• v.wave.point(x,y)

• v.wave.packX(list), v.wave.packY(list)

• v.wave.outBuffer_ready:

• write False, wait till True

Operating System

• Vectoros!

• Runs menu system

• Buttons and LEDs

• Uses asyncio: define functions async and be sure to yield

• Lets you map your code to A/B/C/D.py

Micropython

• Why Micropython?

• Interactive REPL to control vectorscope is awesome

• Two cores: one just for you

• Filesystem

• Secret trick: Hold down the [User] Button on boot

Creature Comforts

• Thonny IDE: configure to use badge, done

• mpremote: for the CLI aficionado

• mp run file.py, mp cp *.py :, mp mount .

• picotool save -a your_image.uf2

• VS Code stubs

Many Ways to Play

• Use vectorscope.wave, funny graphics and/or sounds

• Go analog!

• Tweak vectorscope

• Don't use vectorscope: GC9A01_mpy library compiled in

• Blow Micropython away and start from scratch (but: codec, screen, keys)

Under the Hood

Credits

• Hackaday Team: Elliot and Al and Tom

• Voja Antonic

• Design Lab: Giovanni, Majenta, Bruce, Keno, and Team

Tales of Woe

{height=500px}

Powers of Ten

{height=500px}

10 ms

{height=500px}

1 ms

{height=500px}

100 us

{height=500px}

10 us

{height=500px}

1 us

{height=500px}

100 ns

{height=500px}

10 ns

{height=500px}

1 ns

{height=500px}

The DMA/PIO Machine

• DMA reads from one location to another

• DMA and memory is Turing complete

• DMA counter

Pixel Pusher

{height=500px}

Badgers!