ZHCSI79B March 2016 – May 2018 TAS5751M
PRODUCTION DATA.
All mixer gain coefficients are 26-bit coefficients using a 3.23 number format. Numbers formatted as 3.23 numbers mean that the binary point has 3 bits to the left and 23 bits to the right. This is shown in Figure 64.
Figure 64. 3.23 Format The decimal value of a 3.23 format number can be found by following the weighting shown in Figure 64. If the most significant bit is logic 0, the number is a positive number, and the weighting shown yields the correct number. If the most significant bit is a logic 1, then the number is a negative number. In the case every bit must be inverted, a 1 added to the result, and then the weighting shown in Figure 65 applies to obtain the magnitude of the negative number.
Figure 65. Conversion Weighting Factors—3.23 Format to Floating Point Gain coefficients, entered via the I²C bus, must be entered as 32-bit binary numbers. The format of the 32-bit number (4-byte or 8-digit hexadecimal number) is shown in Figure 66.
Figure 66. Alignment of 3.23 Coefficient in 32-Bit I²C Word | db | Linear | Decimal | Hex (3.23 Format) |
|---|---|---|---|
| 0 | 1 | 8,388,608 | 80 0000 |
| 5 | 1.77 | 14,917,288 | 00E3 9EA8 |
| –5 | 0.56 | 4,717,260 | 0047 FACC |
| X | L = 10(X / 20) | D = 8,388,608 × L | H = dec2hex (D, 8) |
| db | Linear | Decimal | Hex (9.17 Format) |
|---|---|---|---|
| 0 | 1 | 131,072 | 2 0000 |
| 5 | 1.77 | 231,997 | 3 8A3D |
| –5 | 0.56 | 73,400 | 1 1EB8 |
| X | L = 10(X / 20) | D = 131,072 × L | H = dec2hex (D, 8) |