DA6505.005
11 June 2018
CONFIGURATION REGISTER (EE/6EHEX
)
Configuration
register
(EE/6EHEX
)
contains
pass filtering can be used to damp sudden variations
in the sensor signal and to further improve noise
resolution by an additional filtering of the noise. The
filter does not affect output data rate but it narrows
signal bandwidth and increases step response
delay. See also APPLICATION INFORMATION on
page 40 regarding IIR filter noise resolution
improvement and step response characteristics.
measurement delay and digital infinite inpulse
response (IIR) low pass filter coefficient settings. In
addition the register has configuration bit to select
between 4-wire and 3-wire SPI bus modes. See
table 3.
In normal mode the selected measurements are run
automatically in a loop. There are eight delays from
0.5ms up to 4000ms selectable by DELAY bit
settings.
The FILTER=000 selects no filtering. There are four
filter coefficient options available; COEFF=2, 4, 8 or
16. The IIR filter is initialized every time the FILTER
value is changed. Writing the same FILTER value to
the Configuration register which it already contains
does not initialize the filter. The filtered digital output
code formula is as shown in equation 1 below.
By FILTER bit settings it is possible to select optional
low pass filtering of the output temperature and
pressure results. Filtered temperature and pressure
results are stored into the Temperature result
registers (F4/74…F6/76HEX) and the Pressure result
registers (F1/71…F3/73HEX) respectively. The low
(
)
퐂퐎퐃퐄
∙ 퐂퐎퐄퐅퐅−ퟏ +퐂퐎퐃퐄
퐎퐋퐃
퐀퐃퐂
퐂퐎퐃퐄퐍퐄퐖
where
=
Equation 1
퐂퐎퐄퐅퐅
CODENEW = new filtered output
CODEADC = latest A/D conversion result
COEFF = IIR filter coefficient (2, 4, 8 or 16)
CODEOLD = previous filtered output
Table 3. Configuration register (EE/6EHEX) description
Bit
Bit
Description
Value
Function
Number
Name
7-5
DELAY
Delay between
measurements
000
001
010
011
100
101
110
111
000
001
010
011
other
0
0.5ms
62.5ms
125ms
250ms
500ms
1000ms
2000ms
4000ms
No filtering
2
4
8
16
Default
4-2
FILTER
IIR filter coefficient
1
0
-
-
1
0
1
Reserved for testing purpose. See note.
4-wire in SPI bus mode (default after power up)
3-wire in SPI bus mode
WIRE
SPI 3-wire selection
Note: Keep bit [1] always at logic 0. When STEST=1100 is selected in the Trim and test register (FA/7AHEX) the bit [1] logic 1 selects
external clock for the EEPROM block.
18 (44)
MAS [ MICRO ANALOG SYSTEMS ]
