Sensor modules

AXS-028 — ICS-43434 I2S microphone PMOD module

Catalog #28, level L4 (streaming audio).

Level L4 ERC clean DRC clean Fab package 6 components

3D render of the AXS-028 PCB — Rendered from the PCB layout. No physical board has been manufactured.

Components#

Every placed component, with the reason it is on the board. Extracted directly from the schematic, so this cannot drift from the design.

Ref	Value	What it does on this board	Part number	Footprint
`C1`	100nF 16V X7R	VDD decoupling close to the microphone	`GRM188R71C104KA01D` Murata	`C_0603_1608Metric`
`J1`	PMOD PLUG 2x6	PMOD peripheral plug (Digilent spec 1.2)	not selected generic	`PinHeader_2x06_P2.54mm_Horizontal`
`JP1`	L/R SLOT	I2S slot select: 1-2 LR to GND = left/WS-low (default), 2-3 LR to VDD = right/WS-high	—	`SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm`
`R1`	100R	Series protection on the microphone-driven data line	`RC0603FR-07100RL` Yageo Datasheet ↗	`R_0603_1608Metric`
`R2`	100k	SD idle pull-down: the tri-stated bus reads 0 outside this mic's slot	`RC0603FR-07100KL` Yageo Datasheet ↗	`R_0603_1608Metric`
`U1`	ICS-43434	24-bit I2S digital MEMS microphone, -26 dBFS, 65 dB SNR	`ICS-43434` TDK InvenSense Datasheet ↗	`InvenSense_ICS-43434-6_3.5x2.65mm`

Signals#

Net labels used in the schematic, which are also the names the HDL top level should use.

3V3 GND LR MIC_SD SCK SD WS

Production status#

Schematic ERC	0 violations
PCB layout	complete
DRC	0 violations
Fab package	exported (24 gerbers + drill + CPL + BOM)
Fabricated	no — design stage only

Source: boards/sensor-modules/axs-028-ics43434

Catalog #28 (../README.md), level L4 (streaming audio).

Status: schematic generated, ERC clean (0/0), netlist reviewed. PCB layout not started. Not released.

What it teaches#

The first streaming board: the host generates SCK/WS and deserializes 24-bit two's-complement samples in real time. Natural fabric follow-ups: level meter, FIR filtering, FFT spectrum display. Two modules — one strapped left, one right — form a stereo pair on a shared bus.

Design#

TDK InvenSense ICS-43434, 24-bit I2S, SCK 0.5–3.6 MHz, WS = SCK/64.
SD through 100 Ω series to PMOD 3 (Type 7 ADC-data slot), with a 100 kΩ pull-down so the tri-stated bus reads 0 outside this mic's slot.
L/R slot select on JP1 (default 1-2: left / WS-low).
PMOD map (Type 7 I2S): 1 WS/LRCLK, 3 SD/ADC-data, 4 SCK/BCLK (host is controller).
Layout notes: bottom-port microphone — port hole in the PCB, keep it clear of paste, pour, and soldermask web.

Regenerate / remaining#

python3 generate_design.py — then PCB layout (acoustic port), HDL (i2s_rx core), BOM check, checklist.