STA339BWS datasheet(61/79 Pages) STMICROELECTRONICS

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STA339BWS

Writing a set of coefficients to RAM

Select the RAM block with register 0x31 bit1, bit0.

Write 6-bits of starting address to I2C register 0x16.

Write top 8-bits of coefficient b1 in I2C address 0x17.

Write middle 8-bits of coefficient b1 in I2C address 0x18.

Write bottom 8-bits of coefficient b1 in I2C address 0x19.

Write top 8-bits of coefficient b2 in I2C address 0x1A.

Write middle 8-bits of coefficient b2 in I2C address 0x1B.

Write bottom 8-bits of coefficient b2 in I2C address 0x1C.

Write top 8-bits of coefficient a1 in I2C address 0x1D.

10. Write middle 8-bits of coefficient a1 in I2C address 0x1E.

11. Write bottom 8-bits of coefficient a1 in I2C address 0x1F.

12. Write top 8-bits of coefficient a2 in I2C address 0x20.

13. Write middle 8-bits of coefficient a2 in I2C address 0x21.

14. Write bottom 8-bits of coefficient a2 in I2C address 0x22.

15. Write top 8-bits of coefficient b0 in I2C address 0x23.

16. Write middle 8-bits of coefficient b0 in I2C address 0x24.

17. Write bottom 8-bits of coefficient b0 in I2C address 0x25.

18. Write 1 to WA bit in I2C address 0x26.

The mechanism for writing a set of coefficients to RAM provides a method of updating the

five coefficients corresponding to a given biquad (filter) simultaneously to avoid possible

unpleasant acoustic side-effects. When using this technique, the 6-bit address specifies the

address of the biquad b1 coefficient (for example, 0, 5, 10, 20, 35 decimal), and the

STA339BWS generates the RAM addresses as offsets from this base value to write the

complete set of coefficient data.

Table 72. RAM block for biquads, mixing, scaling, bass management

Index

(Decimal)

Index (Hex)

Description

Coefficient

Default

0x00

Channel 1 - Biquad 1

C1H10(b1/2)

0x000000

0x01

C1H11(b2)

0x000000

0x02

C1H12(a1/2)

0x000000

0x03

C1H13(a2)

0x000000

0x04

C1H14(b0/2)

0x400000

0x05

Channel 1 - Biquad 2

C1H20

0x000000

……

…

0x13

Channel 1 - Biquad 4

C1H44

0x400000

0x14

Channel 2 - Biquad 1

C2H10

0x000000

0x15

C2H11

0x000000

……

…

0x27

Channel 2 - Biquad 4

C2H44

0x400000

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