Cirrus Logic CS5534-BS - Manual (Page 27)

CS5532/34-BS
DS755F3 27
Filter Rate Select, FRS[19]
0 Use the default output word rates.
1 Scale all output word rates and their corresponding filter characteristics by a factor of 5/6.
NU (Not Used)[18:0]
0 Must always be logic 0. Reserved for future upgrades.
2.4. Setting up the CSRs for a Measurement
The CS5532/34 have four Channel-Setup Registers
(CSRs). Each CSR contains two 16-bit Setups which
are programmed by the user to contain data conver-
sion information such as: 1) which physical channel
will be converted, 2) at what gain will the channel be
converted, 3) at what word rate will the channel be
converted, 4) will the output conversion be unipolar
or bipolar, 5) what will be the state of the output
latch during the conversion, 6) will the converter de-
lay the start of a conversion to allow time for the out-
put latch to settle before the conversion is begun, and
7) will the open circuit detect current source be acti-
vated for that Setup. In addition, when the OGS bit
in the Configuration Register is set, the Setup selects
which set of offset and gain registers to use when
performing conversions or calibrations. Note that a
particular physical input channel can be represent- ed in more than one Setup with different output
rates, gain ranges, etc. (i.e. each Setup is indepen-
dently defined). Refer to section 2.4.1 for more de-
tails about the Channel Setup Registers.
Each 32-bit CSR is individually accessible and
contains two 16-bit Setups. As an example, to con-
figure Setup 1 in the CS5532/34 with the write in-
dividual channel-setup register command (0x05
hexadecimal), bits 31 to 16 of CSR 1 contains the
information for Setup 1 and bits 15 to 0 contain the
information for Setup 2. Note that while read-
ing/writing CSRs, two Setups are accessed in pairs
as a single 32-bit CSR register. Even if one of the
Setups isn’t used, it must be written to or read. Ex-
amples detailing the power of the CSRs are provid-
ed in section 2.6.3.