January 2023: There is now a Sparkfun WM8960 Breakout Board and a feature-complete Arduino driver library. The extensive examples and hookup guide use a SparkFun IoT RedBoard ESP32 with the WM8960 DAC (24bit and 44.1kHz default).
Proto-driver (eventually as a library similar to the STM32 library in the folder STM32-Open103Z), and example applications for Arduino and Teensy MCUs (Note 1), using the Wolfson WM8960 Audio DAC, with separate stereo BTL 1W speaker and headphone amplifiers (common grounded - Note 2), and a fractional-N PLL (which is missing from the the WM8731 DAC), enabling the use of one external crystal supporting most commonly-used audio-clock needs (Note 4 page 60). Note that absent from the Sparkfun driver, the driver here is USBAudio enabled via the Teensy USBAudio libraries - it is a 16bit 44.1kHz USBAudio DAC.
The PLL register values used here seems to be supported by the gdaszuta comment from one of the Raspberry Pi Circle issues regarding a noisy WM8960 Circle driver. The Circle wm8960 sound driver also now use these PLL values.
Note the difference in the headphone output circuit (Note 5), between the Waveshare Raspberry Pi Hat (which similar to the configuration in the Seeed Studio Re-Speaker Hat), and the Waveshare Audio CODEC module. That specific board type and the Teensy, has an better low end range, and also has an LC filter at the headphone plug. The hat type of audio codec module lacks the optional hardware configuration for headphone insert detection, and it needs an additional code to enable manual switching between speaker and headphones (similar to the option in the Linux alsamixer). Currently both outputs are enabled for the hat type board. The other type of audioboard has the headphone auto-detection circuitry enabled.
The standard Teensy main volume control via two mono amplifiers has been added for the hat type board (else only the current windows application control the DAC volume). Setting the WM8960 analog output volume directly through i2c control is also possible.
Subjectively this 2007, 14 year old DAC (Notes 3 and 4) outperforms its specifications. Listening to the same source material through the headphone output on the waveshare wm8960 hat dac, are similar to the listening experience when using the same source material and headphones with a Creative AE-5 (which has a dedicated headphone amplifier). Both module types do not need/have a MCLK connected.
Short interconnect wiring must be used - else 100 to 220 ohm resistors inline for all or some of the i2s signal wiring can be used, as was the case here. 3k9 pullup resistors was also used on the i2c SDA and SCL lines.
Note 1: It is puzzling why a search for an Arduino driver was unsuccessful (August 2020), especially considering that this CODEC is widely used by the Raspberry Pi community, and is still in considerable demand, as seemingly confirmed by Note 4 below.
Note 2: It should be possible to use the BTL speaker outputs isolated through 100uF capacitors, with common ground headphones - refer to the block diagram.
Note 3: See the WM8960-ALSA-driver folder above, for the original 2007-2011 WM8960 ALSA SoC Audio driver from Wolfson Microelectronics (PLC).
Note 4: The latest datasheet from Cirrus Logic for the WM8960 is dated as recent as 2019: WM8960_v4.4.pdf.
Note 5: The headphone output is also used as a line output. On the General DAC type board there is also one input available on the line output jack.
Note 6: Infineon released a 16bit/24bit/32bit and 44.1kHz/48kHz driver for the WM8960 about two years ago (Jul 21, 2021). This driver was recently adapted by pschatzmann for Arduino to use the Wire API. Refer to the Infineon-Arduino-wm8960 section. Also refer to WM8960 Audio Codec Modules for more information on the two Waveshare WM8960 modules.
Note 7: Cirrus Logic has indicated that they will stop manufacturing the WM8960 during 2023. The WM8962B is recommended as a replacement. Note that this is also an old design the linux ALSA driver is dated 2010
Table 1: Connections between WM8960 Raspberry Pi HAT and Teeensy 3x and 4x:
| WM8960 RPi | Teensy 4.x | Teensy 3.x |
|---|---|---|
| 2,4 +5v | +5v | +5v |
| 6 GND | GND | GND |
| 3 SDA | 18 SDA | 18 SDA |
| 5 SCL | 19 SCL | 19 SCL |
| 12 PCM-CLK | 21 BCLK | 9 BCLK |
| 35 PCM-FS | 20 LRCLK | 23 LRCLK |
| 38 PCM-IN | 8 TX | 13 SCK |
| 40 PCM-OUT | 7 RX | 22 |
Table 2: Connections between WM8960 General DAC and Teeensy 3x and 4x:
| WM8960 DAC | Teensy 4.x | Teensy 3.x |
|---|---|---|
| 1,2 +3v3 | +3v3 | +3v3 |
| 3,4 GND | GND | GND |
| 5,6 SDA | 18 SDA | 18 SDA |
| 7,8 SCL | 19 SCL | 19 SCL |
| 9,10 SCLK | 21 BCLK | 9 BCLK |
| 11,12 WS | 20 LRCLK | 23 LRCLK |
| 13 RXSDA | 7 RX | 22 |
| 14 TXSDA | 8 TX | 13 SCK |
| 15,16 MCLK R/T |
Waveshare WM8960 Stereo CODEC General purpose module
Waveshare WM8960 Hi-Fi Sound Card HAT for Raspberry Pi
Teensy 4.1 and Teensy 3.6 with the Waveshare WM8960 Stereo CODEC as USB Audio DAC:
Teensy 4.0 and the Waveshare WM8960 Stereo CODEC as USB Audio DAC:
Teensy 4.0 and the Waveshare WM8960 Raspberry Pi Hat as USB Audio DAC:
This combination of the CODEC and Teensy sounds much better in the low range end due to the LC filter at the headphone plug. It needs a new section of code to enable manual switching between speaker and headphones (similar to the option in the Linux alsamixer). Short interconnect wiring must be used - unlike the photo below.
Raspberry Pi and Waveshare WM8960 as Audio DAC:
The WM8960 CODEC is also used by the Seeed voicecard or ReSpeaker 2-Mics Pi HAT.
