Page 8
4.2 Setting different filter levels
The levels are set by applying a BCD code to three solder jumpers on the underside of the module.
The module can be controlled with a microcontroller. As the DSP employs internal pull-ups, it is not
necessary to drive the microcontroller pins high, they can be placed in a high impedance state.
4.3 Remote setting of DSP filter level
Remote setting of the DSP level may be achieved through the PCB connections at PL2, this allows the
filter level to be changed during operation. If the remote DSP settings are to be used, ensure that
the solder jumpers are removed from NS0 through NS2 as shown below:
To set the DSP level remotely, connect the pins N0, N1 and N2 (PL2 pins 1, 2 and 3 respectively) as
shown in Table 2 below. The DSP Module has internal pull-ups on its inputs, so any cell in the table
cont3.3 V may be taken up to or left open circuit.
Level
N2
N1
N0
1
0 V
0 V
0 V
2
0 V
0 V
+3.3 V
3
0 V
+3.3 V
0 V
4
0 V
+3.3 V
+3.3 V
5
+3.3 V
0 V
0 V
6
+3.3 V
0 V
+3.3 V
7
+3.3 V
+3.3 V
0 V
8
+3.3 V
+3.3 V
+3.3 V
Table 2
–
Remote Pin settings for various Noise Reduction Levels
4.4 Setting the Noise Reduction Level using the On-board Jumper links
The on-board Noise reduction selection jumper selectors are located on the underside of the
Module as shown below. These jumpers are actually PCB pads that should be linked using a solder
bridge. Caution should be used when carrying out this operation to ensure that other components
and connections are not bridged as this could cause the module to malfunction or even fail.
The Noise reduction Level settings
are shown in the table below.
Table 3
–
On-board Jumper setting
Level
NS2
NS1
NS0
1
Open
Open
Open
2
Open
Open Linked
3
Open Linked Open
4
Open Linked Linked
5
Linked Open
Open
6
Linked Open Linked
7
Linked Linked Open
8
Linked Linked Linked
NS0
NS1
NS2
