STA382BW
Register description: Sound Terminal compatibility
Doc ID 022783 Rev 1
139/172
Writing a set of coefficients to RAM
1.
Write 6 bits of the starting address to I
2
C register 0x16.
2.
Write the top 8 bits of coefficient b1 in I
2
C address 0x17.
3.
Write the middle 8 bits of coefficient b1 in I
2
C address 0x18.
4.
Write the bottom 8 bits of coefficient b1 in I
2
C address 0x19.
5.
Write the top 8 bits of coefficient b2 in I
2
C address 0x1A.
6.
Write the middle 8 bits of coefficient b2 in I
2
C address 0x1B.
7.
Write the bottom 8 bits of coefficient b2 in I
2
C address 0x1C.
8.
Write the top 8 bits of coefficient a1 in I
2
C address 0x1D.
9.
Write the middle 8 bits of coefficient a1 in I
2
C address 0x1E.
10. Write the bottom 8 bits of coefficient a1 in I
2
C address 0x1F.
11. Write the top 8 bits of coefficient a2 in I
2
C address 0x20.
12. Write the middle 8 bits of coefficient a2 in I
2
C address 0x21.
13. Write the bottom 8 bits of coefficient a2 in I
2
C address 0x22.
14. Write the top 8 bits of coefficient b0 in I
2
C address 0x23.
15. Write the middle 8 bits of coefficient b0 in I
2
C address 0x24.
16. Write the bottom 8 bits of coefficient b0 in I
2
C address 0x25.
17. Write 1 to the WA bit in I
2
C 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
STA382BW generates the RAM addresses as offsets from this base value to write the
complete set of coefficient data.
Obsolete Product(s) - Obsolete Product(s)
