Lotus Input Module Firmware

See below sections for LED Matrix, LCD Display and C1 Minimal module details.

Rust project setup based off of: https://github.com/rp-rs/rp2040-project-template

Features

• Reset into bootloader when firmware crashes/panics
• API over USB ACM Serial Port - Requires no Drivers on Windows and Linux
  • Display various pre-programmed patterns
  • Light up a percentage of the screen
  • Change brightness
  • Send a black/white image to the display
  • Send a greyscale image to the display
  • Go to sleep
  • Reset into bootloader
  • Scroll and loop the display content vertically
  • A commandline script and graphical application to control it
• Sleep Mode
  • Transition slowly turns off/on the LEDs
  • Current hardware does not have the SLEEP# GPIO connected, can't sleep automatically

Future features:

• API
  • Send a greyscale image to display
  • Read current system state (brightness, sleeping, ...)

Control from the host

Requirements: Python, PySimpleGUI and optionally pillow

Use control.py. Either the commandline, see control.py --help or the graphical version: control.py --gui

options:
  -h, --help            show this help message and exit
  --bootloader          Jump to the bootloader to flash new firmware
  --sleep, --no-sleep   Simulate the host going to sleep or waking up
  --brightness BRIGHTNESS
                        Adjust the brightness. Value 0-255
  --animate, --no-animate
                        Start/stop vertical scrolling
  --pattern {full,lotus,gradient,double-gradient,zigzag,panic,lotus2}
                        Display a pattern
  --image IMAGE         Display a PNG or GIF image in black and white only)
  --image-grey IMAGE_GREY
                        Display a PNG or GIF image in greyscale
  --percentage PERCENTAGE
                        Fill a percentage of the screen
  --clock               Display the current time
  --string STRING       Display a string or number, like FPS
  --symbols SYMBOLS [SYMBOLS ...]
                        Show symbols (degF, degC, :), snow, cloud, ...)
  --gui                 Launch the graphical version of the program
  --blink               Blink the current pattern
  --breathing           Breathing of the current pattern
  --eq EQ [EQ ...]      Equalizer
  --random-eq           Random Equalizer
  --wpm                 WPM Demo
  --snake               Snake
  --all-brightnesses    Show every pixel in a different brightness
  --set-color {white,black,red,green,blue,cyan,yellow,purple}
                        Set RGB color (C1 Minimal Input Module)
  --get-color           Get RGB color (C1 Minimal Input Module)
  -v, --version         Get device version
  --serial-dev SERIAL_DEV
                        Change the serial dev. Probably /dev/ttyACM0 on Linux, COM0 on Windows

Examples

# Launch graphical application
./control.py --gui

# Show current time and keep updating it
./control.py --clock

# Draw PNG or GIF
./control.py --image stripe.gif
./control.py --image stripe.png

# Change brightness (0-255)
./control.py --brightness 50

Control via Rust binary

Currently have to specify the build target because it's not possible to specify a per package build target. Tracking issue: rust-lang/cargo#9406

> cargo build --target x86_64-unknown-linux-gnu -p inputmodule-control
> cargo run --target x86_64-unknown-linux-gnu -p inputmodule-control

Building

Dependencies: Rust

Prepare Rust toolchain:

rustup target install thumbv6m-none-eabi
cargo install flip-link
cargo install elf2uf2-rs --locked

Build:

cargo build -p ledmatrix
cargo build -p b1display
cargo build -p c1minimal

Generate UF2 file:

elf2uf2-rs target/thumbv6m-none-eabi/debug/ledmatrix ledmatrix.uf2
elf2uf2-rs target/thumbv6m-none-eabi/debug/b1display b1dipslay.uf2
elf2uf2-rs target/thumbv6m-none-eabi/debug/b1display c1minimal.uf2

Flashing

First, put the module into bootloader mode, which will expose a filesystem

This can be done by pressing the bootsel button while plugging it in.

cargo run -p ledmatrix
cargo run -p b1display
cargo run -p c1minimal

Or by copying the above generated UF2 file to the partition mounted when the module is in the bootloder.

Check the firmware version of the device

In-band using control.py

> ./control.py --version
Device version: 0.1.2

By looking at the USB descriptor

On Linux:

> lsusb -d 32ac: -v 2> /dev/null | grep -P 'ID 32ac|bcdDevice'
Bus 003 Device 078: ID 32ac:0021 Framework Lotus B1 Display
  bcdDevice            0.10

Panic

On panic the RP2040 resets itself into bootloader mode. This means a new firmware can be written to overwrite the old one.

Additionally the panic message is written to flash, which can be read as follows:

sudo picotool save -r 0x15000000 0x15004000 message.bin
strings message.bin | head

LED Matrix

It's a 9x34 (306) LED matrix, controlled by RP2040 MCU and IS31FL3741A LED controller.

Connection to the host system is via USB 2.0 and currently there is a USB Serial API to control it without reflashing.

B1 Display

C1 Minimal Input Module

It's a very minimal input module. Many GPIO pins are exposed so that headers can be soldered onto them. Additionally there are pads for a WS2812/Neopixel compatible RGB LED.

When booting up this LED is lit in green color. Its color and brightness can be controlled via the commands:

> ./control.py --brightness 255
> ./control.py --get-brightness
Current brightness: 255

> ./control.py --set-color yellow
> ./control.py --get-color
Current color: RGB:(255, 255, 0)