MAS3507D Micronas Intermetall, MAS3507D Datasheet - Page 36

• Manufacturer Part Number: MAS3507D
• Description: Mpeg 1/2 Layer 2/3 Audio Decoder
• Manufacturer: Micronas Intermetall

MAS 3507D
3.7.2.1. PLL Offset for 44/48 kHz Sampling Frequency
With these memory cells it is possible to choose other
frequencies than the standard CLKI frequencies.
Please note:
– PLLOffset48 is valid for
– PLLOffset44 is valid for
Table 3–16 shows the default values which will be set
by the firmware according to the start-up configuration.
Table 3–16: PLLOffset48 and PLLOffset44
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:
– Calculate the PLLOffsets according to:
– Write the PLLOffsets to the memory (PLLOffset48
– Send a ‘run $475’ command. With the jump to this
36
Address
D0:$36d
D0:$36e
f
14.725 MHz
f
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.
D0:$36d, PLLOffset44 D0:$36e).
address, the settings in the memory will be valid for
the internal processing.
s
s
f
CLKI
= 48, 24, 12, 32, 16, or 8 kHz.
= 44.1, 22.05, 11.025 kHz.
=
--------------------------------------------- -
13
+
24,576 8
PLLOffset48
PLLOffset48
0.351986
R/W
r/w
r/w
Name
PLLOffset48
PLLOffset44
=
--------------------------------------------- -
13
+
22,5792 8
PLLOffset44
PLLOffset44
0.732862
Function
PLL offset (if f
validate by ‘run $475’ command
PLL offset (if f
validate by ‘run $475’ command
Table 3–17: f
Example:
A very common crystal frequency is 14.31818 MHz
(NTSC color subcarrier). The
and
are inside the range 0.74 ... 0.74.
PLLOffset
0.74
0.74
PLLOffset48
PLLOffset44
s
s
= 48, 24, 12, 32, 16, or 8 kHz),
= 44.1, 22.05, 11.025 kHz),
ClkI
f
related to
48 kHz
16.0365 MHz
14.309 MHz
CLKI
for max./ min. PLLOffsets
=
=
for f
24,576 8
----------------------- - 13
14,31818
22,5792 8
-------------------------- - 13
14,31818
PRELIMINARY DATA SHEET
s
–
–
fCLKI for fs
related to
44.1 kHz
14.7336 MHz
13.1465 MHz
=
=
0,7314
–
0,3843
Default
Micronas