Nortel Networks MSC8101 ADS user manual Audio Codec, 5831 CS4221 Programming

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

Functional Description

ethernet transceiver may be Disabled / Enabled at any time via the MII’s MDIO port.

The LXT970 is able to interrupt the MSC8101, this via IRQ7~ line. This line is shared also with the CPM expansion connectors. Therefore, any tool that is connect to IRQ7 or IRQ6~ for that matter, should drive these lines only with an Open Drain buffer.

5•8•3 Audio CODEC

The CS4221 is a highly integrated, high performance, 24-bit, audio CODEC providing stereo ADC and stereo DAC converters using delta-sigma conversion techniques.The device operates from a single +5V power supply and provides digital interface 3.3V.

Control for the functions available on the CODEC device over SPI port of the MSC8101.

External crystal must be equal 11.289MHz for master mode with sample rate frequency Fs equal to 44.1kHz.

The chip controlled by CODEC_EN bit in BCSR1/1. To enable CODEC device operation the CODEC_EN bit should be set to zero (default setting).

FIGURE 5-4 MSC8101 to CODEC connection.

MSC8101		To Exp. Connector
	6	BCSR1/1
CPM
		CODECENb	CS4221
TDMA1
	U22	HRESET	RST	AINL+/-	MIC
on MCC1
CLK1			SCLK		Input
CLK2
				AINR+/-
L1TSYNC			LRCK		Line
L1RSYNC
			SDIN		Input
L1TXD
L1RXD			SDOUT	AONL+/-	To stereo
		P.D.*		AONR+/-
					Amp.

	XTI XTO	SPI pins
* Master Mode select		2
		To SPI port
11.289MHz
			CPM

5•8•3•1 CS4221 Programming

After power-up the CODEC device needs to be initialized over SPI port of the CPM. The pulldown resistor on SDOUT pin causes the part operates in Clock Master Mode. To communicate with the CS4221 the chip address field must be ‘001000’. The control register contains eight bytes which are selected by memory address pointer of three LSB. The programming values are shown in TABLE 5-7. "CS4221 Programming" below:

TABLE 5-7. CS4221 Programming

Byte	Function	Value	Meaning:
Num.
1	ADC Control	‘0’	Default. Normal mode. High Pass Filter active
2	DAC Control	‘0/60’	Default/Both channels are muted
3,4	OUT Attenuator	‘00’	Default. No attention.
	Data
5	DSP Mode	‘0F’	44.1 kHz de-emphasis setting, I/O serial data format is
			right justified 20 bit

MOTOROLA MSC8101ADS RevB User’s Manual 51

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