Demo Payload

See python_payload/README.md for a demo application.

Files can be transferred either by performing an idf.py flash or with mpremote, such as:

mpremote fs cp python_payload/main.py :main.py

Alternatively, adafruit-ampy may work more reliably sometimes:

ampy -p /dev/ttyACM0 -d3 put main.py

Please transfer all .py files in python_payload/ for using the demo payload.

How to install dependencies

Pay attention to install version 5.1. To be sure follow the generic instructions below.

Generic

1. install esp-idf v5.1: (copied from https://www.wemos.cc/en/latest/tutorials/others/build\_micropython\_esp32.html)

$ cd ~
$ git clone https://github.com/espressif/esp-idf.git
$ cd esp-idf
$ git checkout v5.1
$ git submodule update --init --recursive

$ cd esp-idf
$ ./install.sh
$ source export.sh

best put something like "alias espidf='source ~/esp-idf/export.sh'" in your .bashrc etc, you need to run it in every new terminal and adding it to autostart did bother us

Nix(OS)

$ nix-shell nix/shell.nix

How to build and flash

Standard ESP-IDF project machinery present and working. You can run idf.py from the git checkout and things should just work.

Building

Prepare submodules:

git submodule update --init --recursive

Build normally with idf.py:

$ idf.py build

By default, code for the fourth generation prototype will be built. To select a different generation, either set -g/--generation during an idf.py build (which will get cached for subsequent builds) or set the BADGE_GENERATION environment variable to one of the following values:

Important: when switching generations, do a full clean by running rm -rf sdkconfig build. Otherwise you will get weird errors and likely will end up building for the wrong architecture.

Flashing

Put badge into bootloader mode by holding left should button down during boot.

$ idf.py -p /dev/ttyACM0 flash

The following targets are available for flashing:

You can skip -p /dev/ttyACM0 if you set the environment variable ESPPORT=/dev/ttyACM0. This environment variable is also set by default when using Nix.

After flashing, remember to powercycle your badge to get it into the user application.

Cleaning

For a full clean, do not trust idf.py clean or idf.py fullclean. Instead, do:

$ rm -rf build sdkconfig

Accessing MicroPython REPL:

$ picocom -b 115200 /dev/ttyACM0
$ # or
$ screen /dev/ttyACM0
$ # or (will eat newlines in REPL, though)
$ idf.py -p /dev/ttyACM0 monitor
$ # or
$ mpremote repl /dev/ttyACM0

and press Ctrl-C (potentially twice) to exit the debug output.

Use CMake

idf.py calls cmake under the hood for most operations. If you dislike using wrappers you can do the same work yourself:

mkdir build
cd build
cmake .. -G Ninja
ninja

There's flash/monitor targets, too (but no openocd/gdb...). To pick what port to flash to/monitor, set the ESPPORT environment variable.

How to modify

Structure

main/               - main module, starts micropython on core1 and continues
                      executing components/badge23/.
usermodule/         - `hardware`, `synth`, ... C modules exposed to micropython.
components/badge23/ - main ESP-IDF `app_main`, runs on core 0 after micropython
                      gets started on core1.
components/gc9a01/  - low-level LCD driver.

General info

Global + micropython entry point: app_main() in micropython/ports/esp32/main.c, compiled into main/ component.

C entry point, called by^: os_app_main() in components/badge23/espan.c

Register new C files for compilation: add to components/badge23/CMakelists.txt

Debugging

The badge is currently configured to run in HW USB UART/JTAG mode (vs. using TinyUSB and 'software' CDC/whatever using the generic OTG peripheral).

What this means:

1. You can use the MicroPython REPL over a USB console,
2. The MicroPython REPL will also print ESP-IDF logs, including panics,
3. You can use OpenOCD/GDB.

printf() debugging and logging in C-land

Given the above, you can do the following to get a log. This is part of ESP-IDF's standard logging functionality.

static const char *TAG = "misery";
// ...
ESP_LOGI(TAG, "i love C");

However, this will only work if you first set CONFIG_LOG_DEFAULT_LEVEL_INFO=y (which will likely break programs interacting with micropython REPL as many components of the ESP-IDF will suddenly become very chatty). But that's fine for troubleshooting some C-land bugs.

If you want to only log errors or just add temporary logs, use ESP_LOGE instead, which will always print to the USB console.

printf() also just works. But it should only be used for development debugging, for long-term logging statements please use ESP_LOG* instead.

Running OpenOCD+GDB

First, make sure your badge is running in application mode (not bootloader mode! that will stay in bootloader mode).

Then, start OpenOCD:

$ OPENOCD_COMMANDS="-f board/esp32s3-builtin.cfg" idf.py openocd

(you can skip setting OPENOCD_COMMANDS if you're using Nix)

Then, in another terminal:

$ idf.py gdb

Good luck. The idf.py gdb/openocd scripts seem somewhat buggy.

ESP-IDF functionality

sdkconfig / menuconfig

We have an sdkconfig.defaults file. It is used to generate a '.generated' file with flow3r-specific options based on the given -g option. See the build instructions above to see how to select the generation to build against.

The build system will generate an sdkconfig, but it should not be committed into version control. Instead, treat it like an ephemeral artifact that you can also modify for your own needs during development.

To run menuconfig, do the usual::

$ idf.py  menuconfig

(Specify -g or BADGE_GENERATION if you haven't built the firmware yet)

Then, either save into the temporary sdkconfig by using 'S', or save into a defconfig by using 'D'. The resulting build/defconfig file can then be copied into sdkconfig to change the defaults for a given generation (be sure to remove FLOW3R_* options that are usually generated by idf_ext.py).

Badge link

Badge link lets you have UART between badges or other devices using a 3.5mm audio cable.

Baud rates up to 5mbit are supported in theory, but data corruption is likely with higher rates.

Use baud rate 31250 for MIDI.

Note that badge_link.enable() will refuse to enable line out if the cable is not connected. Connect it first. Connecting headphones with badge link enabled is not recommended, especially not when wearing them.

Example usage:

On both badges:

import badge_link
from machine import UART
badge_link.enable(badge_link.PIN_MASK_ALL)

On badge 1, connect the cable to line out, and configure uart with tx on tip (as an example)

uart = UART(1, baudrate=115200, tx=badge_link.PIN_INDEX_LINE_OUT_TIP, rx=badge_link.PIN_INDEX_LINE_OUT_RING)

On badge 2, connect the cable to line in, and configure uart with tx on ring:

uart = UART(1, baudrate=115200, tx=badge_link.PIN_INDEX_LINE_IN_RING, rx=badge_link.PIN_INDEX_LINE_IN_TIP)

Then write and read from each side:

uart.write("hiiii")
uart.read(5)

Documentation

To build sphinx docs:

cd docs
make html
firefox _build/html/index.html

To continuously build on change:

watchexec make html

License

All original source code in this reporitory is Copyright (C) 2023 Flow3r Badge Contributors. This source code is licensed under the GNU General Public License Version 3.0 as described in the file COPYING.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License Version 3.0 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License Version 3.0 along with this program. If not, see https://www.gnu.org/licenses/.