Production Data
WM8580
w
PD, Rev 4.7, March 2009
55
•
PLL User Mode (Selected if S/PDIF Receiver Disabled)
In user mode, the user has full control over the function and operation of both PLLA and PLLB. In
this mode, the user can accurately specify the PLL N and K multiplier values and the pre and post-
scale divider values and can hence fully control the generated clock frequencies.
Refer to Table 47 and Table 49 for details of the registers available for configuration in this mode.
REGISTER
ADDRESS
BIT LABEL DEFAULT
DESCRIPTION
R0
PLLA 1/
DEVID1
00h
8:0 PLLA_K[8:0] 100100001
R1
PLLA 2/
DEVID2
01h
8:0 PLLA_K[17:9] 101111110
3:0 PLLA_K[21:18]
1101
Fractional (K) part of PLLA
frequency ratio II .
Value K is one 22-digit binary
number spread over registers R0,
R1 and R2 as shown.
R2
PLLA 3/
DEVREV
02h
7:4
PLLA_N[3:0]
0111
Integer (N) part of PLLA frequency
ratio. I
Use values in the range 5
≤
PLLA_N
≤
13 as close as possible to 8
R4
PLLB 1
04h
8:0 PLLB_K[8:0] 100100001
R5
PLLB 2
05h
8:0 PLLB_K[17:9] 101111110
3:0 PLLB_K[21:18]
1101
Fractional (K) part of PLLB
frequency ratio I.
Value K is one 22-digit binary
number spread over registers R4,
R5 and R6 as shown.
Note: PLLB_K must be set to
specific values when the S/PDIF
receiver is used. Refer to S/PDIF
Receive Mode Clocking section
for details.
R6
PLLB 3
06h
7:4
PLLB_N[3:0]
0111
Integer (N) part of PLLB frequency
rat atioII(R).
Use values in the range 5
≤
PLLB_N
≤
13 as close as possible to 8
Note: PLLB_N must be set to
specific values when the S/PDIF
receiver is used. Refer to S/PDIF
Receive Mode Clocking section
for details.
Table 47 User Mode PLL_K and PLL_N Multiplier Control
PARAMETER
PLL USER
MODE
PLL S/PDIF RECEIVER MODE
PRESCALE_A
Manual
Write PRESCALE_B Value
PRESCALE_B
Manual
Configure Specified PLLB Frequency
PLLA_N Manual Automatically Controlled
PLLA_K Manual Automatically Controlled
PLLB_N
Manual
Configure Specified PLLB Frequency
PLLB_K
Manual
Configure Specified PLLB Frequency
FREQMODE_A Manual
Automatically Controlled
FREQMODE_B Manual
Not
Used
POSTSCALE_A Manual 256fs/128fs
PLLACLK
Select
POSTSCALE_B Manual
Not
Used
Table 48 PLL Control Register Function in PLL User and PLL S/PDIF Receiver Modes
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