CS2000-CP

18

DS761PP1

5.3.3

Manual Ratio Modifier (R-Mod)

Table 2 on page 18.

The R-Mod value selected by RModSel[2:0] is always used in the calculation for the Effective Ratio

its default value of ‘000’, which corresponds to an R-Mod value of 1, thereby effectively disabling the ratio

modifier.

Table 2. Ratio Modifier

5.3.4

Automatic Ratio Modifier (Auto R-Mod) - Hybrid PLL Mode Only

The Automatic R-Modifier uses the status of the CLK_IN Frequency Range Indicator (see section 5.2.1

Table 3.

ifier is enabled by the AutoRMod bit.

Table 3. Automatic Ratio Modifier

It is important to note that Auto R-Mod (if enabled) is applied in addition to any R-Mod already selected

by the RModSel[2:0] bits and is used to calculate the Effective Ratio (see Section 5.3.5 on page 19).

Auto R-Mod can be used to generate the appropriate oversampling clock (MCLK) for audio A/D and D/A

converters. For example, if the clock applied to CLK_IN is the audio sample rate, Fs (also known as the

word, frame or Left/Right clock), and SysClk is 12.288 MHz (REF_CLK = 12.288 MHz with RefClkDiv[1:0]

RModSel[2:0]

Ratio Modifier

000

1

001

2

010

4

011

8

100

0.5

101

0.25

110

0.125

111

0.0625

Referenced Control

Register Location

Ratio0-3.................................“Ratio 0 - 3 (Address 06h - 15h)” on page 30

RModSel[2:0] ........................ “R-Mod Selection (RModSel[2:0])” section on page 28

FsDetect[1:0]

Auto R Modifier

00

> 224

1

01

96 - 224

0.5

10

< 96

0.25