# ADAU1467 Hardware Architecture - Status: Draft - Date: 2026-08-01 - Document Type: Component Architecture # 1. Overview The ADAU1467 is the central audio processor of HubAudio. It represents the boundary between: - Control Domain - Audio Domain - Time Domain The device provides: - SigmaDSP processing - digital audio routing - serial audio interfaces - clock generation - self boot capability The ADAU1467 is not considered a simple peripheral but the master component of the Audio Domain. --- # 2. Functional Role The ADAU1467 performs: - DSP execution - audio mixing - signal routing - sample rate management - digital audio synchronization The ESP32-S3 configures the ADAU1467 but does not process real-time audio. Architecture: ESP32-S3 | | SPI | ADAU1467 | | I2S Audio Peripherals --- # 3. Power Architecture The ADAU1467 requires separated power domains. Main domains: Digital Supply DVDD | Digital core Analog Supply AVDD | PLL and analog sections Interface Supply IOVDD | Digital interfaces Power design rules: - local decoupling on every supply pin - clean analog supply - short return paths - separation between noisy digital regulators and audio rails The ADAU1467 power domains must be integrated with the HubAudio power architecture. --- # 4. Master Clock Architecture The ADAU1467 uses an external reference clock. Target audio clock family: 12.288 MHz 48 kHz × 256 Clock chain: 12.288 MHz Reference | ADAU1467 | Internal PLL | Audio Clock Domain | MCLK / BCLK / LRCLK The ADAU1467 defines the timing reference of the Audio Domain. --- # 5. Clock Distribution The ADAU1467 clock output can be distributed using a dedicated clock buffer. ADAU1467 Clock Master | MCLK | PCS2P2309NZ Clock Buffer +-----------+-----------+ | | | CODEC BT Radio The PCS2P2309NZ provides fan-out and signal integrity improvement. It does not generate the audio clock. --- # 6. SPI Control Interface The ADAU1467 provides an SPI control interface. Connection: ESP32-S3 SPI MASTER | | ADAU1467 SPI SLAVE Used for: - configuration - parameter update - status monitoring --- # 7. Self Boot EEPROM The ADAU1467 supports self boot from external EEPROM. HubAudio implementation: ADAU1467 SPI MASTER | 25AA1024 EEPROM | DSP Program During normal operation: - ESP32 configures the ADAU1467 - ADAU1467 manages its DSP memory The EEPROM remains part of the Audio Processor domain. --- # 8. Serial Audio Interfaces The ADAU1467 provides multiple serial audio ports. HubAudio allocation: Inputs: SDATA_IN0 ESP32-S3 SDATA_IN1 Si4684 SDATA_IN2 Optical DECODEC SDATA_IN3 Bluetooth RX Outputs: SDATA_OUT0 CODEC SDATA_OUT1 Bluetooth TX SDATA_OUT2 Optical ENCODEC The ADAU1467 operates as audio timing master. --- # 9. Boot Sequence Power ON | ESP32-S3 startup | Configure ADAU1467 | ADAU1467 loads DSP program | Audio clocks enabled | Audio peripherals synchronized | System ready --- # 10. PCB Design Requirements Critical signals: - MCLK - BCLK - LRCLK - SPI - I2S DATA Layout rules: - continuous ground reference - short clock traces - avoid RF proximity - local decoupling - controlled return currents The ADAU1467 section should be treated as a high-performance mixed-signal audio subsystem. --- # 11. Design Philosophy The ADAU1467 is the conductor of the HubAudio orchestra. The ESP32-S3 provides instructions. The peripherals provide instruments. The ADAU1467 defines timing, routing and processing.