Cirrus Logic AN298 - Manual (Page 23)

AN298RC14 23
6 PCM Firmware Module
6 PCM Firmware Module
6.1 Overview
The PCM firmware module provides routing and control functions for stereo and multi-channel PCM input. The PCM
firmware is co-resident with the OS module. There are two main modes of PCM operation, stereo and multi-channel.
6.2 PCM Manager
Index = 0xHHHH, data value = 0xhhhhhhhh
Write = 0x9B00HHHH 0xhhhhhhhh
Read Request = 0x9BC0HHHH
Read Response = 0x1BC0HHHH 0xhhhhhhhh
Table 6-1. PCM Manager
Index Variable Description
0x0000 PCM_ENABLE Bit 16 = Disable/Enable decimation by 4 = 0/1
Bit 8 = Disable/Enable Decimation by 2 = 0/1
Note: This setting is valid for stereo and multi-channel PCM inputs. When decimator
(down sampler) is enabled, set SAMPLE_RATE (index 0x03) in OS Manager as follows:
0 = 96 kHz in 48 kHz out
1 = 88.2 kHz in 44.1 kHz out
2 = 64 kHz in 32 kHz out
Sample rate conversion is supported only for stereo and 8-channel inputs.
Bit 4 = Disable/Enable De-emphasis = 0/1
Bit 0 = Disable/Enable PCM Module = 0/1
Default = 0x00000001
0x0001 IO_BUFF_CH0_SOURCE Input Source for Channel 0 IO Buffer (Left) (see Table 2-1 )
Default = 0x00000000 (DAI0 Left)
0x0002 IO_BUFF_CH1_SOURCE Input Source for Channel 1 IO Buffer (Center) (see Table 2-1 )
Default = 0x00000004 DAI2 Left)
0x0003 IO_BUFF_CH2_SOURCE Input Source for Channel 2 IO Buffer (Right) (see Table 2-1 )
Default = 0x00000001 (DAI0 Right)
0x0004 IO_BUFF_CH3_SOURCE Input Source for Channel 3 IO Buffer (Left Surround) (see Table 2-1 )
Default = 0x00000002 (DAI1 Left)
0x0005 IO_BUFF_CH4_SOURCE* Input Source for Channel 4 IO Buffer (Right Surround) (see Table 2-1 )
Default = 0x00000003 (DAI1 Right)
0x0006 IO_BUFF_CH5_SOURCE* Input Source for Channel 5 Left IO Buffer (Surround Back) (see Table 2-1 )
Default = 0x00000006 (DAI3 Left)
0x0007 IO_BUFF_CH6_SOURCE* Input Source for Channel 6 IO Buffer (Surround Back Right) (see Table 2-1 )
Default = 0x00000007 (DAI3 Right)
Product
Number
I/O_Config (See Table 4-1 , Index 0x0001)
Bit 2 Bit 1 Bit 4
CS49860 Supported Not Supported Not Applicable
CS48540 Supported Supported Not Applicable
CS48520 Supported Not Supported Supported