MAS 3507D
PRELIMINARY DATA SHEET
3.7.2.1. PLL Offset for 44/48 kHz Sampling Frequency
Address
R/W Name
Function
Default
D0:$36d
r/w
PLLOffset48
PLL offset (if fs = 48, 24, 12, 32, 16, or 8 kHz),
validate by ‘run $475’ command
D0:$36e
r/w
PLLOffset44
PLL offset (if fs = 44.1, 22.05, 11.025 kHz),
validate by ‘run $475’ command
With these memory cells it is possible to choose other
frequencies than the standard CLKI frequencies.
Please note:
Table 3–17: fClkI for max./ min. PLLOffsets
PLLOffset fCLKI for fs
related to
fCLKI for fs
related to
44.1 kHz
– PLLOffset48 is valid for
fs = 48, 24, 12, 32, 16, or 8 kHz.
48 kHz
– PLLOffset44 is valid for
fs = 44.1, 22.05, 11.025 kHz.
−0.74
16.0365 MHz
14.309 MHz
14.7336 MHz
13.1465 MHz
0.74
Table 3–16 shows the default values which will be set
by the firmware according to the start-up configuration.
Example:
Table 3–16: PLLOffset48 and PLLOffset44
A very common crystal frequency is 14.31818 MHz
(NTSC color subcarrier). The
fCLKI
PLLOffset48
PLLOffset44
24,576 8
-----------------------
PLLOffset48 =
– 13 = 0,7314
14.725 MHz
0.351986
−0.732862
14,31818
and
It is also possible to run the MAS 3507D with other
clocks. In broadcast mode, it is necessary to adjust the
PLLOffsets to this clock, otherwise it will not lock to the
MPEG bit stream. In multimedia mode, it is recom-
mended to adjust the PLLOffsets to the crystal, other-
wise it would result in a frequency shift (music will be
played faster or slower). For adjusting, the following
procedure must be done:
22,5792 8
--------------------------
PLLOffset44 =
– 13 = –0,3843
14,31818
are inside the range −0.74 ... 0.74.
– Calculate the PLLOffsets according to:
24,576 8
13 + PLLOffset48
22,5792 8
13 + PLLOffset44
--------------------------------------------- ---------------------------------------------
=
f
=
CLKI
with −0.74 < PLLOffset < 0.74. This corresponds to
a frequency range of 14.31...14.73 MHz for the
crystal, if both 44.1 kHz and 48 kHz based sample
frequencies are used. The range is extended in an
application with a fixed sampling frequency, as
Table 3–17 shows.
– Write the PLLOffsets to the memory (PLLOffset48
D0:$36d, PLLOffset44 D0:$36e).
– Send a ‘run $475’ command. With the jump to this
address, the settings in the memory will be valid for
the internal processing.
36
Micronas
MICRONAS [ MICRONAS ]
