6M48下YPBPR、HDMI、USB通道开机有哮叫声
关键字：YPBPR HDMI USB 哮叫声(杂音)
适用机种：6M181/182 6M48 6M309/306
PCB Layout走线如果不合理的话，会导致在某些特定通道下，如上面所说的YPBPR等，开机时听到一些哮叫声（或者叫杂音）。其实，这些杂音属于高频底噪,通过软件是可以改善的。具体做法如下：
int main(void)
{
......
//Added for reduce audio backnoise
{
MUTE_On();
MsOS_DelayTask(100);
MDrv_WriteByte(0x112AA2,0X03);
MDrv_WriteByte(0x112CFA,0X00);
MDrv_WriteByte(0x112CFB,0X08);
MsOS_DelayTask(100);
MUTE_Off();
}
while ( 1 )
{
#ifdef ENABLE_LOAD_APP_FROM_USB
if((g_bDebugProgStopFlag)&&(flag==FALSE))
{
U8 name[]="APP.BIN";
extern BOOLEAN LoadAppbyFileNameFromUSB(U8 *fn);
flag=LoadAppbyFileNameFromUSB(name);
MsOS_DelayTask( 5000 );
}
#endif
#if (ENABLE_MSTV_UART_DEBUG)
if ( msAPI_UART_DecodeCommand() )
{
#if ( !CHANNEL_SCAN_AUTO_TEST )
#if ( WATCH_DOG == ENABLE )
msAPI_Timer_ResetWDT();
#endif
continue; // stop main loop for debug
#endif
}
if ( g_bDebugProgStopFlag )
{
#if ( WATCH_DOG == ENABLE )
msAPI_Timer_ResetWDT();
#endif
continue;
}
#endif
MApp_MultiTasks();
#if 0 // MFC debug
MDrv_MFC_PrintMessage();
if(g_ucRegNums)
continue;
#endif
MApp_TopStateMachine();
#ifdef ENABLE_MINI_DUMP
if(!IsStorageInUse())
{
MiniDump_MountDrive();
}
#endif
#ifdef MSOS_TYPE_LINUX
system_polling();
#endif
}//main while end
return 0;
}
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