WM8731PMOD

A small board to extend audio capabilities to FPGA via PMOD interface. Designed with lceda。

It includes:

1. WM8731 chip with I2C and I2S
2. PAM8303 + XH2.54 2P for speaker output
3. 4x TRS port for line in, mic in, line out and headphone out
4. PMOD connection to FPGA

PMOD pin definition

Description	Pin number	Pin number	Description
SPEAKER_MUTE	7	1	I2S_LRCLK
MCLK	8	2	I2S_DACDAT
I2C_SCL	9	3	I2S_ADCDAT
I2C_SDA	10	4	I2S_BCLK
GND	11	5	GND
VCC	12	6	VCC

TRS definition

1. Line in: T(Left) R(Right) S(Ground)
2. Microphone in: T(Left) R(Ground) S(Ground)
3. Line out: T(Left) R(Right) S(Ground)
4. Headphone out: T(Left) R(Right) S(Ground)

Project

Online version is available at oshwhub.com/jiegec/wm8731mod。

Schematic, PCB, Gerber and BOM files are included in this repo.

Example code: jiegec/Arty-A7-WM8731PMOD.

Errata

#1: PMOD interface flipped

Version affected: 2021-03-07, 2021-03-09

PMOD interface is flipped in direction, so you need to flip the board to match the correct pin mapping.

Cost

Manufacture in JLC:

1. 5 pcs PCB: 5.0 CNY + tax 0.4 CNY
2. 5 pcs SMT: Components 126.18 CNY(WM8731 16.05 CNY/pcs, PAM8303 2.51 CNY/pcs) + Other fees 154.4 CNY(Extended library 60 CNY, Engineering 50 CNY, SMT pad 5.9 CNY, Hand weld pad 18.5 CNY, Hand engineering 20 CNY) + Tax 22.45 CNY

Total: 61.686 CNY/pcs.

References

• A similar project
• DE2 board schematic

Version history

2024-04-09

1. Replace some BOM

2021-04-29

1. Fixed typo: WM7831 -> WM8731

2021-04-13

1. Fixed errata #1: PMOD interface flipped

2021-03-09

1. Add support for speaker: XH2.54P connector and PM8303 amplifiier
2. Add output selector to choose one of: speaker and line out left

2021-03-07

1. Initial version with WM8731 and four audio jacks

License

Licensed under CERN-OHL-P.