STA381BW datasheet(82/171 Pages) STMICROELECTRONICS

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STA381BW

82/171

Doc ID 018835 Rev 7

Writing a set of coefficients to RAM

Write 6 bits of the starting address to I2C register 0x27.

Write the top 8 bits of coefficient b1 in I2C address 0x28.

Write the middle 8 bits of coefficient b1 in I2C address 0x29.

Write the bottom 8 bits of coefficient b1 in I2C address 0x2A.

Write the top 8 bits of coefficient b2 in I2C address 0x2B.

Write the middle 8 bits of coefficient b2 in I2C address 0x2C.

Write the bottom 8 bits of coefficient b2 in I2C address 0x2D.

Write the top 8 bits of coefficient a1 in I2C address 0x2E.

Write the middle 8 bits of coefficient a1 in I2C address 0x2F.

10. Write the bottom 8 bits of coefficient a1 in I2C address 0x30.

11. Write the top 8 bits of coefficient a2 in I2C address 0x31.

12. Write the middle 8 bits of coefficient a2 in I2C address 0x32.

13. Write the bottom 8 bits of coefficient a2 in I2C address 0x33.

14. Write the top 8 bits of coefficient b0 in I2C address 0x34.

15. Write the middle 8 bits of coefficient b0 in I2C address 0x35.

16. Write the bottom 8 bits of coefficient b0 in I2C address 0x36.

17. Write 1 to the WA bit in I2C address 0x37.

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

STA381BW generates the RAM addresses as offsets from this base value to write the

complete set of coefficient data.

STA381BW датащи(PDF) 82 Page - STMicroelectronics