Low-power audio front-end低功耗音频前端
Bringing up an audio path on ARM Cortex-M33 where a codec, DMA controller and wake-up path meet at one timing edge.在 ARM Cortex-M33 上启动一条音频路径：编解码器、DMA 控制器和唤醒流程在同一个时序边沿相遇。
- State状态Working note进行中的笔记
- Boundary边界Codec · DMA · ISR
- Budget预算< 10 ms wake
Public scope公开范围
The useful public story is the debugging boundary: clock readiness, peripheral ownership and which interrupt should own the first clean sample. Product identity, schematics, registers, traces and measured results stay private.可以公开的重点是调试边界：时钟何时稳定、外设所有权如何交接，以及哪个中断应当拥有第一帧干净采样。产品身份、原理图、寄存器、trace 和测量结果保持私密。
- Explicit power and ownership states显式的电源与所有权状态
- Firmware timestamps beside hardware observation将固件时间戳与硬件观测并列
- No invented outcome while the work remains in progress项目仍在进行中，不虚构结果