🚧 Experimental repository

Early-stage development only.
No support is provided yet. Use at your own risk.

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Satellite1-RPi

Raspberry Pi SDK for the Satellite1-HAT

This repository contains all components required to run the Satellite1-HAT on a Raspberry Pi Zero W2:

• satellite1-rpi — Python SDK library
• satellite1-rpi-setup — Raspberry Pi configuration packaged as a .deb
• rpi-kernel-fusb302 — Custom Raspberry Pi kernel with USB-C Power Delivery support
• image-builder — Generates SD-card images with everything preinstalled

Target Platform: Raspberry Pi Zero W2
OS: Raspberry Pi OS (Bookworm)

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Table of contents

• Quick start
• RPi Setup
• CLI Usage
• Development

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Quick start

Flash the Satellite1 SDK Image

The easiest way to set up the Satellite1-HAT is to flash the prepared Satellite1 SDK Image.
This image includes:

• Raspberry Pi OS (Bookworm)
• Custom kernel with FUSB302 USB-C PD support
• All necessary overlays and configuration
• The Satellite1 Python SDK + CLI
• Automatic DAC initialization at boot

Steps:

1. Install Raspberry Pi Imager
2. In Application Settings, set:
   Content Repository → <your repository URL>
3. Select the Satellite1 SDK Image
4. Flash it to an SD card
5. Boot the Raspberry Pi Zero W2 with the Satellite1-HAT installed

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RPi Setup

1. Kernel with USB-C Power Delivery Support

The default kernel shipped with Raspberry Pi OS does not include support for USB-C Power Delivery.

Install the custom kernel:

sudo dpkg -i linux-image-6.12.58-fusb302-rpi-v8_2_arm64.deb

This kernel includes:

CONFIG_TYPEC=m
CONFIG_TYPEC_TCPM=m
CONFIG_TYPEC_TCPCI=m
CONFIG_TYPEC_FUSB302=m

Reboot after installation.

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2. Device Tree Overlays and Module Configuration

Install the setup package:

sudo dpkg -i satellite1-rpi-setup_1.0-1_arm64.deb

Installs and configures:

• FUSB302 overlay (USB-C PD)
• Satellite1 I²S audio overlay
• /etc/alsa/conf.d/50-satellite1.conf
• Loads i2c-dev on startup
• Enables SPI, I²S, and I2C in /boot/firmware/config.txt
• Adds sensor overlay:
  i2c-sensor,addr=0x38,chip=aht20

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3. Python Satellite1 SDK

sudo dpkg -i satellite1-rpi-sdk_0.1.5_arm64.deb

This will:

• Create a venv at /opt/satellite1/venv
• Install the Satellite1 Python library
• Install the sat1 CLI in /usr/bin/sat1
• Install satellite1-init.service (initializes DACs at boot)

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CLI Usage

The sat1 CLI provides control over:

• DAC
• XMOS
• USB-C PD

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Global Usage

sat1 [-h] [--config CONFIG] [-v] {dac,xmos,pd} ...

Components

Component	Description
dac	DAC audio controls
xmos	XMOS interface and firmware controls
pd	USB-C PD contract status

Options

Option	Description
-h, --help	Show help
--config FILE	Custom TOML config (default /etc/satellite1.conf)
-v, --verbose	Increase verbosity

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DAC Controls

sat1 dac [options] {volume,set-volume,mute,unmute,setup,plugged-in,status}

Commands

Command	Description
volume	Read current volume
set-volume	Set volume
mute	Mute line-out
unmute	Unmute line-out
setup	Initialize DAC
plugged-in	Detect headphone jack
status	Show status

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DAC Selection

--dac {auto,line-out,speaker}

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Line-Out Overrides

Option	Description
--line-out-enabled / --no-line-out-enabled	Enable/disable line-out
--line-out-startup-volume <0..1>	Initial volume
--line-out-startup-muted / --no-line-out-startup-muted	Mute at startup
--line-out-restore-on-startup / --no-line-out-restore-on-startup	Restore previous state

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Speaker Overrides

Option	Description
--speaker-enabled / --no-speaker-enabled	Enable/disable speaker
--speaker-startup-volume <0..1>	Startup volume
--speaker-startup-muted / --no-speaker-startup-muted	Mute at startup
--speaker-restore-on-startup / --no-speaker-restore-on-startup	Restore previous state
--speaker-channel {left,right,dwn_mix}	Output routing
--speaker-amp-level <int>	Amplifier gain

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XMOS Controls

sat1 xmos {setup,read-firmware,read-status,reset,enable-flashing,disable-flashing,run-spi-test,set-mic-output,flash-firmware}

Commands

Command	Description
setup	Initialize SPI/GPIO
read-firmware	Read firmware version
read-status	Read status register
reset	Toggle reset
enable-flashing	Enter flashing mode
disable-flashing	Exit flashing mode
run-spi-test	SPI echo test
set-mic-output	Configure I²S microphone routing
flash-firmware	Flash XMOS firmware

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Power Delivery

sat1 pd

Shows current USB-C Power Delivery contract.

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Development

More documentation coming soon.