TAS5727
www.ti.com
SLOS670 –NOVEMBER 2010
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 35.
Fraction
Digit 6
Sign
Bit
Fraction
Digit 1
Fraction
Digit 2
Fraction
Digit 3
Fraction
Digit 4
Fraction
Digit 5
Integer
Digit 1
u
u
u
u
u
u
x
x.
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x x x x
0
S
Coefficient
Digit 8
Coefficient
Digit 7
Coefficient
Digit 6
Coefficient
Digit 5
Coefficient
Digit 4
Coefficient
Digit 3
Coefficient
Digit 2
Coefficient
Digit 1
u = unused or don’t care bits
Digit = hexadecimal digit
M0127-01
Figure 35. Alignment of 3.23 Coefficient in 32-Bit I2C Word
Table 2. Sample Calculation for 3.23 Format
db
0
Linear
1
Decimal
8,388,608
14,917,288
4,717,260
Hex (3.23 Format)
80 0000
5
1.77
00E3 9EA8
–5
X
0.56
L = 10(X/20)
0047 FACC
D = 8,388,608 × L H = dec2hex (D, 8)
Table 3. Sample Calculation for 9.17 Format
db
0
Linear
1
Decimal
131,072
Hex (9.17 Format)
2 0000
5
1.77
231,997
3 8A3D
–5
X
0.56
L = 10(X/20)
73,400
1 1EB8
D = 131,072 × L
H = dec2hex (D, 8)
Copyright © 2010, Texas Instruments Incorporated
Submit Documentation Feedback
29
Product Folder Link(s): TAS5727
TI [ TEXAS INSTRUMENTS ]
