Battery-less Audio Node Design
Table
| Net | Purpose |
|---|---|
| 5V_IN | External bench input to LDO VIN and EN |
| 3V3 | Main regulated rail for U1, MK1, and debug header |
| GND | Common return path |
| PDM_CLK | U1 PC00 to MK1 CLOCK |
| PDM_DATA | MK1 DATA to U1 PC01 |
| PDM_SELECT | MK1 SELECT tied low through R2 for low-channel PDM timing |
| RESET_N | U1 RESETn, pull-up R1, reset button S1, and debug header |
| SWCLK | U1 PA01 to debug header |
| SWDIO | U1 PA02 to debug header |
| HFXTAL_I / HFXTAL_O | 38.4 MHz crystal candidate Y1 |
| RF_MATCH_IC | U1 RF2G4_IO side of RF match |
| RF_ANT | SMA antenna/test connector side of RF match |
| COIL_A / COIL_B | Experimental coil/rectenna AC input |
| VHARV | Rectified harvested DC reservoir |
| HARV_SENSE | Divider output to U1 PA03 for firmware measurement |
Architecture Implemented
Functional Blocks
Power Budget
Key Schematic Nets
Datasheet-Grounded Design Choices
Current Review Status
Known Follow-Up Before Layout