sta013b STMicroelectronics, sta013b Datasheet - Page 20

• Manufacturer Part Number: sta013b
• Description: Mpeg 2.5 Layer Iii Audio Decoder
• Manufacturer: STMicroelectronics

STA013 - STA013B - STA013T
PLLFRAC_441_H
Address: 0x52
Type: R/W
Software Reset: 0x00
Hardware Reset: 0x00
The registers are considered logically concate-
nated and contain the fractional values for the
PLL, for 44.1KHz reference frequency.
(see also PLLFRAC_L and PLLFRAC_H regis-
ters)
The Oversampling Factor (O_FAC) is related to OCLK and SCKT by the following expression:
1) OCLK_freq = O_FAC * LRCKT_ Freq
2) OCLK_ Freq = 2 * (1+PCM_DIV) * 32*
3) OCLK_ Freq = 2 * (1+PCM_DIV) * 64*
4) PCM_DIV = (O_FAC/64) - 1 in 16 bit mode
5) PCM_DIV = (O_FAC/128) - 1 in 32 bit mode
Example for setting:
for 16 bit PCM Mode
O_FAC = 512 ; PCM_DIV = 7
O_FAC = 256 ; PCM_DIV = 3
O_FAC = 384 ; PCM_DIV = 5
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PF15 PF14 PF13 PF12 PF11 PF10 PF9
MSB
b7
(DAC relation)
LRCKT_Freq (when 16 bit PCM mode is used)
LRCKT_Freq (when 32 bit PCM mode is used)
MSB
PD7
b7
0
0
0
0
0
0
b6
PD6
b6
0
0
0
0
0
0
b5
b4
PD5
b5
0
0
0
0
0
0
b3
PD4
b4
0
0
0
0
0
0
b2
PD3
b1
b3
0
0
0
0
0
0
LSB
PF8
b0
PD2
b2
1
1
0
0
0
0
PCMDIVIDER
Address: 0x54
Type: RW
Software Reset: 0x03
Hardware Reset: 0x03
PCMDIVIDER is used to set the frequency ratio
between the OCLK (Oversampling Clock for
DACs), and the SCKT (Serial Audio Transmitter
Clock).
The relation is the following:
for 32 bit PCM Mode
O_FAC = 512 ; PCM_DIV = 3
O_FAC = 256 ; PCM_DIV = 1
O_FAC = 384 ; PCM_DIV = 2
PD7
PD1
7
b1
1
0
1
1
1
0
PD6
6
SCKT_freq =
LSB
PD0
b0
1
1
1
1
0
1
PD5
5
PD4
16 bit mode
16 bit mode
16 bit mode
32 bit mode
32 bit mode
32 bit mode
4
2 (1 + PCM_DIV)
PD3
OCLK_freq
3
Description
PD2
2
512 x Fs
384 x Fs
256 x Fs
512 x Fs
384 x Fs
256 x Fs
PD1
1
PD0
0