11 current and voltage ac offset register ( v, 12 pulseratee, Cs5461a – Cirrus Logic CS5461A User Manual
Page 30: Register, 13 temperature register ( t ), 14 system gain register ( sys
CS5461A
30
DS661F3
6.11 Current and Voltage AC Offset Register ( V
ACoff
, I
ACoff
)
Address: 16 (Current AC Offset); 17 (Voltage AC Offset)
Default = 0x000000
The AC Offset Registers (V
ACoff
, I
ACoff
)
are initialized to zero on reset, allowing for uncalibrated normal operation.
AC Offset Calibration updates these registers. This sequence lasts approximately (6N + 30) ADC cycles (where
N is the value of the Cycle Count Register). DRDY will be asserted at the end of the calibration. These values
may be read and stored for future system AC offset compensation. The value is represented in two's comple-
ment notation and in the range of -1.0
V
ACoff
, I
ACoff
1.0, with the binary point to the right of the MSB.
6.12 PulseRateE
3
Register
Address: 18
Default = 0xFA0000 = 32000.00 Hz
PulseRateE
3
sets the frequency of the E3 pulses. The register’s smallest valid frequency is 2
-4
with 2
-5
incre-
mental steps. A pulse rate higher than (MCLK/K)/8 will result in a pulse rate setting of (MCLK/K)/8. The value
is represented in unsigned notation, with the binary point to the right of bit #5.
6.13 Temperature Register ( T )
Address: 19
T contains measurements from the on-chip temperature sensor. Measurements are performed during continu-
ous conversions, with the default the Celsius scale (
o
C). The value is represented in two's complement notation
and in the range of -128.0
T 128.0, with the binary point to the right of the eighth MSB.
6.14 System Gain Register ( SYS
Gain
)
Address: 20
Default = 0x500000 = 1.25
System Gain (SYS
Gain
) determines the one’s density of the channel measurements. Small changes in the mod-
ulator due to temperature can be fine adjusted by changing the system gain. The value is represented in two's
complement notation and in the range of -2.0
SYS
Gain
2.0, with the binary point to the right of the second
MSB.
MSB
LSB
-(2
0
)
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
.....
2
-17
2
-18
2
-19
2
-20
2
-21
2
-22
2
-23
MSB
LSB
2
18
2
17
2
16
2
15
2
14
2
13
2
12
2
11
.....
2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
MSB
LSB
-(2
7
)
2
6
2
5
2
4
2
3
2
2
2
1
2
0
.....
2
-10
2
-11
2
-12
2
-13
2
-14
2
-15
2
-16
MSB
LSB
-(2
1
)
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
.....
2
-16
2
-17
2
-18
2
-19
2
-20
2
-21
2
-22