Skip to content
Auvra

References

Consolidated sources for the Auvra blueprint. Each subsystem document also carries its own Pandoc footnotes; this is the master list, grouped by topic. Accessed June 2026.

Compute platform & board

Section titled “Compute platform & board”
  1. ASRock — N100DC-ITX product specification. https://www.asrock.com/mb/Intel/N100DC-ITX/index.asp
  2. ASRock — N100DC-ITX User Manual (PDF). https://download.asrock.com/Manual/N100DC-ITX.pdf
  3. ASRock — Intel N100 series BIOS Setup Guide (PDF). https://download.asrock.com/Manual/Software/Intel%20N100/Software_BIOS%20Setup%20Guide_English.pdf

I²C, USB bridges & microcontrollers

Section titled “I²C, USB bridges & microcontrollers”
  1. Linux kernel — i2c-i801 driver documentation (Alder Lake SMBus; SPD/sensor use). https://docs.kernel.org/i2c/busses/i2c-i801.html
  2. Microchip — MCP2221A USB-to-I²C/UART bridge. https://www.microchip.com/en-us/product/mcp2221a
  3. Linux kernel — hid-mcp2221 driver source. https://github.com/torvalds/linux/blob/master/drivers/hid/hid-mcp2221.c
  4. Linux kernel — i2c-tiny-usb driver source. https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-tiny-usb.c
  5. gschorcht — i2c-ch341-usb (out-of-tree CH341A driver). https://github.com/gschorcht/i2c-ch341-usb
  6. Adafruit — FT232H breakout Linux setup (userspace libftdi). https://learn.adafruit.com/adafruit-ft232h-breakout/linux-setup
  7. Adafruit — MCP2221A breakout (#4471). https://www.adafruit.com/product/4471
  8. Raspberry Pi — RP2350 datasheet (I²C target, ADC, PIO, stepping). https://datasheets.raspberrypi.com/rp2350/rp2350-datasheet.pdf
  9. Wikipedia — RP2350 (errata / A3-A4 stepping). https://en.wikipedia.org/wiki/RP2350
  10. All About Circuits — I²C design mathematics: capacitance and resistance. https://www.allaboutcircuits.com/technical-articles/i2c-design-mathematics-capacitance-and-resistance/

Real-time Linux & tuning

Section titled “Real-time Linux & tuning”
  1. Phoronix — Real-Time PREEMPT_RT support merged for Linux 6.12. https://www.phoronix.com/news/Linux-6.12-Does-Real-Time
  2. Linux Foundation — PREEMPT_RT versions (wiki). https://wiki.linuxfoundation.org/realtime/preempt_rt_versions
  3. Debian — linux-image-rt-amd64 (Trixie). https://packages.debian.org/trixie/linux-image-rt-amd64
  4. Canonical — Real-time Ubuntu 24.04 LTS. https://ubuntu.com/blog/real-time-24-04
  5. Canonical — Tuning a real-time kernel (IRQ affinity, isolcpus, cyclictest). https://ubuntu.com/blog/real-time-kernel-tuning
  6. LinuxCNC forum — Intel N100 latency thread (N100DC-ITX, isolcpus=1,2,3). https://forum.linuxcnc.org/18-computer/50817-intel-n100
  7. Linux Foundation — SMI latency debugging guide. https://wiki.linuxfoundation.org/realtime/documentation/howto/debugging/smi-latency/start
  8. rtcqs — Real-time config quick scan (Python). https://codeberg.org/rtcqs/rtcqs
  9. Intel — ECI Linux OS runtime optimizations. https://eci.intel.com/docs/3.0/development/optimizations.html

Audio stack & latency

Section titled “Audio stack & latency”
  1. LinuxMusicians — Which gives lowest latency, PipeWire or JACK? https://linuxmusicians.com/viewtopic.php?t=27901

Embedded image build & silent boot

Section titled “Embedded image build & silent boot”
  1. Incredibuild — Yocto vs Buildroot. https://www.incredibuild.com/blog/yocto-or-buildroot-which-to-use-when-building-your-custom-embedded-systems
  2. marcusfolkesson — meta-readonly-rootfs-overlay (Yocto SquashFS + OverlayFS). https://github.com/marcusfolkesson/meta-readonly-rootfs-overlay
  3. ArchWiki — Silent boot. https://wiki.archlinux.org/title/Silent_boot

Audio interfaces

Section titled “Audio interfaces”
  1. RME — Babyface Pro FS (class-compliant, balanced XLR). https://rme-audio.de/babyface-pro-fs.html
  2. MOTU — M4 (4× balanced TRS, class-compliant). https://motu.com/en-us/products/m-series/m4/
  3. MOTU — UltraLite-mk5 specs (10× balanced TRS). https://motu.com/en-us/products/gen5/ultralite-mk5/specs/
  4. PhilippeBekaert — snd-hdspe (RME HDSPe AIO/AIO Pro driver). https://github.com/PhilippeBekaert/snd-hdspe
  5. Schroedingers-Cat — snd-hdspe (maintained fork, newer kernels). https://github.com/Schroedingers-Cat/snd-hdspe
  6. PhilippeBekaert — hdspeconf (HDSPe userspace config tool). https://github.com/PhilippeBekaert/hdspeconf
  7. geoffreybennett — fcp-support (Focusrite Control Protocol tools). https://github.com/geoffreybennett/fcp-support

Keybed, scanning & MIDI

Section titled “Keybed, scanning & MIDI”
  1. Syntaur — Keys not responding correctly? Check the contact strips (two-contact velocity). https://blog.syntaur.com/?p=38
  2. E. Bruchez — Fixing a Yamaha Clavinova CLP-280 (passive L/M/H membrane contacts). https://blog.bruchez.name/posts/fixing-yamaha-clavinova-clp-280/
  3. Syntaur — Yamaha S90 XS repair parts (ribbon cables). https://syntaur.com/keyboard.php?keyboard=Yamaha_S90+XS
  4. P. Drongowski — Yamaha MODX: Inside stuff (E-GKS scanner, I²C “EBUS”). http://sandsoftwaresound.net/yamaha-modx-inside-stuff/
  5. PJRC forum — Converting a Yamaha keyboard assembly with a Teensy (CVP-409/509 smart keybed, I²C). https://forum.pjrc.com/index.php?threads/converting-a-yamaha-keyboard-assembly-with-a-teensy-to-a-midi-controller.35858/
  6. MIDI Association — Jitter and latency: USB / FireWire / Thunderbolt. https://midi.org/community/midi-connections/jitter-and-latency-usb-firewire-thunderbolt
  7. MIDI throughput, latency & jitter (USB-MIDI ~500 µs avg; DIN ~32 µs). https://calcsandcomps.blogspot.com/2021/10/midi-throughput-latency-jitter.html
  8. MicroPython — issue #8167 (RP2040 hardware-I²C clock-stretch failures). https://github.com/micropython/micropython/issues/8167
  9. floretan — p150 (Yamaha P150 + Teensy keybed scanner). https://github.com/floretan/p150
  10. oxesoft — keyboardscanner (multi-keyboard Arduino scanner). https://github.com/oxesoft/keyboardscanner
  11. djbottrill — RP2040_Midi_Scanner (RP2040 keybed scanner). https://github.com/djbottrill/RP2040_Midi_Scanner
  12. chamodhk — midi_keyboard (RP2040 + TinyUSB MIDI). https://github.com/chamodhk/midi_keyboard
  13. Doepfer — DIY 88-key matrix schematic (canonical reference). http://www.doepfer.de/DIY/Matrix_88.gif

Displays

Section titled “Displays”
  1. Waveshare — 7EP-CAPLCD (7″ HDMI + USB capacitive). https://www.waveshare.com/7ep-caplcd.htm
  2. Waveshare — 10.1DP-CAPLCD wiki (10.1″ HDMI + USB capacitive). https://www.waveshare.com/wiki/10.1DP-CAPLCD

Development environment (Phase 1 & 2)

Section titled “Development environment (Phase 1 & 2)”
  1. Phoronix — SDL2 now transitioning to maintenance mode. https://www.phoronix.com/news/SDL2-To-Maintenance-Mode
  2. SDL wiki — README-kmsbsd (kmsdrm backend, DRM-master/permissions). https://wiki.libsdl.org/SDL3/README-kmsbsd
  3. SDL wiki — README-macos (Cocoa). https://wiki.libsdl.org/SDL3/README-macos
  4. SDL Discourse — Building SDL3 for input with KMSDRM display (open input bug, 2025–26). https://discourse.libsdl.org/t/building-sdl3-for-getting-input-with-kmsdrm-display/62294
  5. SDL wiki — SDL_HINT_MOUSE_TOUCH_EVENTS. https://wiki.libsdl.org/SDL3/SDL_HINT_MOUSE_TOUCH_EVENTS
  6. RtAudio — cross-platform audio (CoreAudio/ALSA/JACK). https://github.com/thestk/rtaudio
  7. RtMidi — cross-platform MIDI (CoreMIDI/ALSA-seq/JACK). https://github.com/thestk/rtmidi
  8. PortAudio — audio I/O alternative. https://github.com/PortAudio/portaudio
  9. Apple — Transfer MIDI information between apps (IAC Driver). https://support.apple.com/guide/audio-midi-setup/transfer-midi-information-between-apps-ams1013/mac
  10. VMPK — Virtual MIDI Piano Keyboard. https://vmpk.sourceforge.io/
  11. JUCE — juce_audio_devices (portable-core/per-OS-backend reference). https://github.com/juce-framework/JUCE/blob/master/modules/juce_audio_devices/juce_audio_devices.cpp
  12. picoloop — SDL + RtAudio + RtMidi synth precedent. https://github.com/yoyz/picoloop
  13. QEMU — USB emulation docs (device model API, in-tree build). https://qemu.readthedocs.io/en/master/system/devices/usb.html
  14. QEMU — hw/usb/dev-serial.c (FTDI model + chardev backend template). https://github.com/qemu/qemu/blob/master/hw/usb/dev-serial.c
  15. qemu-devel — Bonzini: emulate a USB-I²C bridge (2014). https://lists.nongnu.org/archive/html/qemu-devel/2014-02/msg02440.html
  16. Linux — hid-mcp2221 driver source (emulation spec). https://raw.githubusercontent.com/torvalds/linux/master/drivers/hid/hid-mcp2221.c
  17. Linux — i2c-stub documentation. https://docs.kernel.org/i2c/i2c-stub.html
  18. raw-gadget — userspace USB device emulation. https://github.com/xairy/raw-gadget
  19. UTM issue #7530 — macOS USB exclusive-access limitation (2025). https://github.com/utmapp/UTM/issues/7530
  20. QEMU 6.2.0 release notes — Apple Silicon HVF support. https://www.qemu.org/2021/12/14/qemu-6-2-0/

FPGA platform, PCIe & network audio

Section titled “FPGA platform, PCIe & network audio”
  1. Sipeed — Tang Mega 138K Pro Dock (GW5AST-138, PCIe 3.0, SFP+, DDR3, AE350). https://en.wiki.sipeed.com/hardware/en/tang/tang-mega-138k/mega-138k-pro.html
  2. Sipeed — Install IDE (Gowin part selection and GW5AST-138 B/C device revision warning). https://wiki.sipeed.com/hardware/en/tang/common-doc/get_started/install-the-ide.html
  3. Gowin — IP and Reference Design catalog and EULA notice. https://www.gowinsemi.com/en/support/ip/
  4. Gowin — PCI Express Controller and IPUG1020 user guide. https://www.gowinsemi.com/en/support/ip_detail/128/
  5. Gowin — RISC-V AE350 SoC. https://www.gowinsemi.com/en/support/ip_detail/111/
  6. Gowin — ASRC and IPUG939 user guide. https://www.gowinsemi.com/en/support/ip_detail/217/
  7. Gowin — 10G Ethernet MAC and IPUG1084 user guide. https://www.gowinsemi.com/en/support/ip_detail/168/
  8. Gowin — 10G Serial Ethernet. https://www.gowinsemi.com/en/support/ip_detail/161/
  9. Gowin — Gowin Software Tcl Commands, SUG100. https://www.gowinsemi.com/upload/database_doc/3262/document/68b8a001a6a92.pdf
  10. Sure Electronics — AA-AB41164 A2D-PCM1822 stereo ADC, differential/single-ended analog to I²S. https://store.sure-electronics.com/product/813
  11. Sure Electronics — AA-AB41166 ASCM-D2A-PCM5122 stereo I²S DAC, differential XLR and single-ended analog output. https://store.sure-electronics.com/product/829

Verification status. Product specs, driver repositories, and the PREEMPT_RT mainline merge were checked against primary sources in June 2026. The Sipeed board interface list and Sure Electronics ADC/DAC product descriptions were rechecked on 2026-09-26. These establish available interfaces, not an assembled or measured Auvra card. Latency figures are indicative and must be re-measured on the assembled instrument (see 10-roadmap-and-risks.md). The S90-specific keybed and panel pinouts are not established here and must be measured on the physical unit.