Listing DSP.PAS 

Unit DSP; 

Interface 

{ ResetDSP returneaza True daca resetarea a } 

{ avut loc cu succes base trebuie sa fie 1 } 

{ pentru adresa de baza $210,2 pentru $220? } 

function ResetDSP(base:Word):Boolean; 

{ WriteDAC setează nivelul de iesire al } 

{ difuzoarelor } 

procedure WriteDAC(level:Byte); 

{ ReadDAC citeste nivelul de intrare al } 

{ microfonului } 

function ReadDAC:Byte; 

{ SpeakerOn conecteaza DAC-ul la difuzoare } 

function SpeakerOn:Byte; 

{ SpeakerOff deconecteaza DAC-ul de la } 

{ difuzoare; nu afecteaza restul } 

{ operatiilor DAC-ului } 

function SpeakerOff: byte; 

{ Functii pentru controlul redarii DMA } 

procedure DMAStop;procedure DMAContinue; 

{ Playback reda un esantion de o marime data } 

{ la o frecventa data folosind canalul 1 DMA } 

{ Esantionul nu trebuie sa treaca de o pagina } 

procedure Playback(sound:Pointer; size:Word; 

frequency:Word); 

Implementation 

Uses Crt; 

var DSP_RESET:Word; 

DSP_READ_DATA:Word; 

DSP_WRITE_DATA:Word; 

DSP_WRITE_STATUS:Word; 

DSP_DATA_AVAIL:Word; 

function ResetDSP(base:Word):Boolean; 

begin 

base:=base*$10; 

{ Calculeaza adresele porturilor } 

DSP_RESET:=base+$206; 

DSP_READ_DATA:=base+$20A; 

DSP_WRITE_DATA:=base+$20C; 

DSP_WRITE_STATUS:=base+$20C; 

DSP_DATA_AVAIL:=base+$20E; 

{ Reseteaza DSP-ul si produce niste pauze } 

{ lungi pentru siguranta } 

Port[DSP_RESET]:=1; Delay(10); 

Port[DSP_RESET]:=0; Delay(10); 

ResetDSP:=(Port[DSP_DATA_AVAIL] and 

$80=$80) and (Port[DSP_READ_DATA]=$AA) 

end; 

procedure WriteDSP(value:Byte); 

begin 

while Port[DSP_WRITE_STATUS] and $80<>0 do; 

Port[DSP_WRITE_DATA]:=value 

end; 

function ReadDSP:Byte; 

begin 

while Port[DSP_DATA_AVAIL] and $80=0 do; 

ReadDSP:=Port[DSP_READ_DATA] 

end; 

procedure WriteDAC(level:Byte); 

begin WriteDSP($10); WriteDSP(level) end; 

function ReadDAC:Byte; 

begin WriteDSP($20); ReadDAC:=ReadDSP end; 

function SpeakerOn:Byte; 

begin WriteDSP($D1) end; 

function SpeakerOff:Byte; 

begin WriteDSP($D3) end; 

procedure DMAContinue; 

begin WriteDSP($D4) end; 

procedure DMAStop; 

begin WriteDSP($D0) end; 

procedure Playback(sound:Pointer;size:Word; 

frequency:Word); 

var time_constant:Word; 

page,offset:Word; 

begin 

SpeakerOn; 

size:=size-1;{ Pregateste controlerul DMA } 

offset:=Seg(sound^) shl 4+Ofs(sound^); 

page:=(Seg(sound^)+Ofs(sound^) shr 4)shr 12; 

Port[$0A]:=5; Port[$0C]:=0; Port[$0B]:=$49; 

Port[$02]:=Lo(offset); 

Port[$02]:=Hi(offset); Port[$83]:=page; 

Port[$03]:=Lo(size); Port[$03]:=Hi(size); 

Port[$0A]:=1; 

{ Seteaza frecventa de redare } 

time_constant:=256-1000000 div frequency; 

WriteDSP($40); 

WriteDSP(time_constant); 

{ Seteaza tipul redarii (8-biti) } 

WriteDSP($14); 

WriteDSP(Lo(size)); WriteDSP(Hi(size)) 

end 

End.