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AN2031 APPLICATION NOTE

3 CONFIGURE STA308A-508//-EVB WITH LPT INTERFACE

1) Plug the LPT Interface on the board utilizing J3 of STA308A-508//-EVB and J2 of LPT Interface;

2) Connect PC parallel port to the LPT board using a parallel cable;

3) Select S/PDIF Input mode (electric or optical) with JP5;

4) Connect logic supply (+5V) on J1 and power supply [10V..35V] on J2;

5) Connect output load on J6;

6) 6Turn on the board;

7) Run STA308A-508PControlPanel.exe on the PC.

3.1 Configuring GUI Software:

1) Go to "Registers" page on GUI.

2) Click "AutoFind LPT" button. It appears the number of LPT port (0x278 or 0x378);

3) Click "Reset" button

4) Click "Power Up" button

5) Click "Test Board I/O". If "passed" it is OK. If "failed", then perform manual board-reset by press-

ing SW1 button and try again. If still "failed" then make sure connections are OK.

6) Go to "Control" page on GUI.

7) Click "Ext Amp Power Up" to enable the output power.

8) Increase "ALL" master volume control.

4 PERFORMANCES

4.1 THD+Noise Ratio versus Output Power at different input power supply Input

frequency: 1KHz; Output load: 4

Ω;

Blue: 15V; Cyan: 20V; Green: 25V; Yellow: 30V; Red: 35V; Magenta: 37V

Figure 1. Audio Precision

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