4.3.10 Audio and External PLL

SAM V71 Xplained Ultra includes a WOLFSON WM8904 Audio CODEC for input and output of digital sound, the kit has two 3.5mm stereo jacks for microphone input and headphone output. There is also an (optional) external PLL, Cirrus Logic CS2100CP, that can be used to generate a reference clock to the WM8904. In an Ethernet AVB application, the CS2100CP PLL can be used to accurately reconstruct a media clock that is generated at a remote network node.

The WM8904 is configured through I²C while audio data is transferred via the SSC module in the SAM V71. The CS2100CP PLL is also configured through I²C, and the input clock reference is from PD21 which is internally connected to the timer unit of the Ethernet MAC in the ATSAMV71Q21.

Table 4-30. *WM8904* Connections
SAM V71 pin	Function	Audio function	Shared functionality
PA03	TWD0	I²C control interface, data line	EXT1, EXT2, EDBG I²C, LCD, Camera, PLL, MediaLB, EEPROM, Crypto, and Shield
PA04	TWCK0	I²C control interface, clock line	EXT1, EXT2, EDBG I²C, LCD, Camera, PLL, MediaLB, EEPROM, Crypto, and Shield
PA10	RD, receiver data	ADCDAT, digital audio output (microphone)	Shield
PA18	PCK2	MCLK, master clock	Shield
PB00	TF, transmitter frame synchronization	LRCLK left/right data alignment clock	EXT1 and Shield (2)
PB01	TK, transmitter clock	BCLK, bit clock, for synchronization	EXT1 and Shield (2)
PD11	GPIO	Interrupt from Audio CODEC	Camera, EXT2, and Shield
PD24	RF, receiver frame synchronization	LRCLK, left/right data alignment clock	Audio, Camera, and Shield
PD26	TD, transmitter data	DACDAT, digital audio input (headphone)	EXT2 and Shield

Table 4-31. *CS2100CP* Connections
SAM V71 pin	Function	Audio function	Shared functionality
PA03	TWD0	I²C control interface, data line	EXT1, EXT2, EDBG I²C, LCD, Camera, Audio, MediaLB, EEPROM, Crypto, and Shield
PA04	TWCK0	I²C control interface, data line	EXT1, EXT2, EDBG I²C, LCD, Camera, Audio, MediaLB, EEPROM, Crypto, and Shield
PD21	TIOA11	REFCLK, PLL input	Camera, EXT1, EXT2, EDBG SPI, and Shield (2)
PA22	RK, receiver clock	PLL output	Shield