STA321MPL 查看數據表（PDF） - STMicroelectronics

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STA321MPL

Scalable digital microphone processor

STMicroelectronics 

Registers

7.5

Writing a single coefficient to RAM

1. Write the top 2 bits of the address to I2C register 0x3B

2. Write the bottom 8 bits of the address to I2C register 0x3C

3. Write the top 8 bits of the coefficient in I2C address 0x3D

4. Write the middle 8 bits of the coefficient in I2C address 0x3E

5. Write the bottom 8 bits of the coefficient in I2C address 0x3F

6. Write 1 to the W1 bit in I2C address 0x4C

STA321MP

7.6

Writing a set of coefficients to RAM

1. Write the top 2 bits of the starting address to I2C register 0x3B

2. Write the bottom 8 bits of the starting address to I2C register 0x3C

3. Write the top 8 bits of coefficient b1 in I2C address 0x3D

4. Write the middle 8 bits of coefficient b1 in I2C address 0x3E

5. Write the bottom 8 bits of coefficient b1 in I2C address 0x3F

6. Write the top 8 bits of coefficient b2 in I2C address 0x40

7. Write the middle 8 bits of coefficient b2 in I2C address 0x41

8. Write the bottom 8 bits of coefficient b2 in I2C address 0x42

9. Write the top 8 bits of coefficient a1 in I2C address 0x43

10. Write the middle 8 bits of coefficient a1 in I2C address 0x44

11. Write the bottom 8 bits of coefficient a1 in I2C address 0x45

12. Write the top 8 bits of coefficient a2 in I2C address 0x46

13. Write the middle 8 bits of coefficient a2 in I2C address 0x47

14. Write the bottom 8 bits of coefficient a2 in I2C address 0x48

15. Write the top 8 bits of coefficient b0 in I2C address 0x49

16. Write the middle 8 bits of coefficient b0 in I2C address 0x4A

17. Write the bottom 8 bits of coefficient b0 in I2C address 0x4B

18. Write 1 to the WA bit in I2C address 0x4C

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 10-bit address specifies the address of the biquad b1

coefficient (for example, decimals 0, 5, 10, 15, …, 100, … 395), and the STA321MP will

generate the RAM addresses as offsets from this base value to write the complete set of

coefficient data.

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Doc ID 022647 Rev 1

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