AN214

AN214 Application Note CS4201/CS4202 SIX CHANNEL AUDIO DESIGN 1. INTRODUCTION This application note describes how to create a six channel AC '97 audio sub-system on a PC motherboard that can accommodate either the CS4201 or the CS4202 audio codec. 2. CS4201/CS4202 DUAL DESIGN Figure 1 illustrates a circuit that accommodates both CS4201 and CS4202 codecs, and Table 1 summarizes the population options. The only changes necessary are to pins 32, 33, 34, and 48. On the CS4201, pins 32-34 form the external connections to the analog 3D filter. Pin 32 is tied to a 0.01 µF capacitor, and a 1000 pF capacitor is connected between pins 33 and 34. The CS4202 implements 3D spatialization in software, therefore filter capacitors C9 and C10 should not be populated. For CS4202 applications not using headphone sense, pin 32 should be tied to ground through a pull-down resistor for software compatibility. See the application note AN215 for information on implementing the CS4202 with headphone sense. The audio driver will read the state of pin 33 on the CS4202 to detect two channel vs. six channel implementation. For six channel operation, pin 33 is tied to digital ground through a pull-down resistor. For information on two channel dual CS4201/CS4202 designs, see the application note AN213. Pin 48 of the CS4201 is used for S/PDIF, or as the second serial data output. On the CS4202, pin 48 is a dedicated S/PDIF output and the second serial data output is located on pin 34. (CS4201)CS4202 U2...