NEDSP900 Development Board
12
6.2
Noise Reduction Control
This is allows the user access to the Noise Reduction control lines of the NEDSP900
module. PL3 has not been fitted. This is a standard 0.1” (2.54mm) Pitch connector and
suggestions for this have been made in section.
The Pin connection and designation is given here:
Pin Signal
Comments
1
Channel 2 – Suppression ON/OFF
Weak Pull-up – Pull Down to Activate
2
Channel 2 – Suppression LSB (NS0)
Weak Pull-up – Pull Down to Activate
3
Channel 2 – Suppression (NS1)
Weak Pull-up – Pull Down to Activate
4
Channel 2 – Suppression MSB (NS2) Weak Pull-up – Pull Down to Activate
5
Channel 1 – Suppression ON/OFF
Weak Pull-up – Pull Down to Activate
6
Channel 1 – Suppression LSB (NS0)
Weak Pull-up – Pull Down to Activate
7
Channel 1 – Suppression (NS1)
Weak Pull-up – Pull Down to Activate
8
Channel 1 – Suppression MSB (NS2) Weak Pull-up – Pull Down to Activate
9
Gnd
10
+5v
You will note from the previous page, that the switches are ON to get the appropriate
line to activate. The NEDSP900 provides a weak pull up to its internal power rail of
1.8Volts, therefore when the switch is activated the appropriate pin is taken to ground.
The logic is therefore inverted. The fact that the ‘weak’ pull-up is to the devices’ 1.8v
internal logic means that caution should be used when attempting to interface with
other logic systems operating at 3.3v or 5v.
The following are a few suggestions as to the possible methods of implementation
Logic control
There are several ways in which the module may be controlled by external logic or
microprocessor. The various alternatives are shown and described below:
Содержание NEDSP900
Страница 17: ...NEDSP900 Development Board 17 Schematic Diagram Sheet 1 of 5 Output Buffer and Line Driver...
Страница 18: ...NEDSP900 Development Board 18 Schematic Diagram Sheet 2 of 5 NEDSP900 and Control Switches...
Страница 19: ...NEDSP900 Development Board 19 Schematic Diagram Sheet 3 of 5 Balanced Audio Inputs See also Appendix B...
