SLOS982C August 2017 – April 2018 TAS5755M
PRODUCTION DATA.
All mixer gain coefficients are 26-bit coefficients using a 3.23 number format. Numbers formatted as 3.23 numbers means that there are 3 bits to the left of the binary point and 23 bits to the right of the binary point. This is shown in Figure 65.
The decimal value of a 3.23 format number can be found by following the weighting shown in Figure 65. 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 this case every bit must be inverted, a 1 added to the result, and then the weighting shown in Figure 66 applied to obtain the magnitude of the negative number.
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 67.
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) |