Option explicit
Option default integer
' pin allocations
Dim Freq =891000, Level = 128
Dim track$
Const CS = 1          ' pin for MCP41010 chip select (CS) pin on module
Const DAT= 2          ' pin for SPI Data
Const CLKP = 4        ' pin for SPI Clk
Const FSY = 5         ' pin for AD9833 chip select(FSY) pin on module
Const ANA = 34        ' pin for analogue sampling if required
Const EXTERNAL=1      ' external analogue sampling enabled
setpins
setfreq
setlevel
if EXTERNAL then
 AUDIO CS,CLKP,DAT,ANA
 Play tone 400,400 'trigger the audio interrupt
 Play pause 'interrupt keeps running during pauses
 Pause 100
 do
 loop
else
 AUDIO CS,CLKP,DAT
 play wav ""
 track$=MM.Info(track)
 If track$<>"OFF" Then Print track$
 Do
   If MM.Info(track)<>track$ Then
     track$=MM.Info(track)
     If track$="OFF" Then end
     Print track$
   EndIf
 
 Loop
endif
'
Sub setpins
 Pin(CS) = 1
 SetPin CS, dout
 Pin(FSY) = 1
 SetPin FSY, dout
 Pin(DAT) = 0
 SetPin DAT, dout
 Pin(CLKP) = 1
 SetPin CLKP, dout
 SetPin ANA,ain
End Sub

Sub SetFreq
 Local f, c, f1, f2
 Const oscillator = 25000000   'Crystal frequency
 Const p = &B1100000000000000
 Const B28 = &H2000
 Const RESET = &H100

 f = (Freq * (1 << 28)) \ oscillator
 f1 = (f And &H3FFF) Or &H4000
 f2 = (f >> 14) Or &H4000

 Pin(FSY) = 0
 s16 c Or RESET Or B28
 s16 f1
 s16 f2
 s16 p
 s16 c
 Pin(FSY) = 1
End Sub

' sets the digital potentiometer (0-255)
' note that when running on 3.3V the maximum undistorted level is 211
Sub SetLevel
 Pin(CS) = 0
 s16 level Or &H1100
 Pin(CS) = 1
End Sub

Sub s16 a%
Local i%, j%
For i% = 15 To 0 Step -1
 j%=1<<i%
 If a% And j% Then
   Pin(DAT)=1
 Else
   Pin(DAT)=0
 EndIf
 Pin(CLKP)=0
 Pause 1
 Pin(CLKP)=1
 Pause 1
Next
End Sub
CSub AUDIO 'CSpin, CLKpin, DATpin [,ANApin]
 0000002C
 'audio
 46C6B5F0 00044E25 000D6833 4B246818 681B2105 4798B500 68D86833 D1382800
 19644B20 01E0681B 4B1F8819 4798681B 26802388 4303015B 4698B29B 4D172710
 02364C17 682BE014 68982106 47986823 2105682B 68236858 46C04798 2106682B
 68236858 46C04798 08763F01 D0082F00 421E4643 682BD1E7 68982105 47986823
 682BE7E6 68182106 47986823 46B8BC80 4B06BDF0 4798681B E7C91100 1000038C
 10000328 100003DC 100003D8 10000324
 'main
 46C6B5F0 B084B500 A8010006 0003001D 46904C16 000F447C C306CC06 801A8822
 D0042E00 D0022F00 2B004643 4B10D102 4798681B 68314B0F 6011681A 6839681A
 46416051 6809681A 681B6091 D00A2D00 60DA682A 4A094B08 447A681B B004601A
 46B8BC80 60DDBDF0 46C0E7F4 00000068 10000368 1000038C 100003D4 FFFFFEF3
 206E6950 6F727245 00000072
End CSub

#include "PicoCFunctions.h"
#include <stdint.h>
#define CSpin CFuncRam[0]
#define CLKpin CFuncRam[1]
#define DATpin CFuncRam[2]
#define ANApin CFuncRam[3]
static void audio(uint16_t left, uint16_t right){
 uint16_t v;
 PinSetBit(CSpin,LATCLR);
 if(ANApin==0)v=(IDiv(((int)left+(int)right)*128L,AUDIO_WRAP)) | 0x1100;
 else v=(uint16_t)(ExtInp(ANApin)>>4) | (uint16_t)0x1100;
 for(uint16_t i=32768;i>=1;i>>=1){
   if(v & i)PinSetBit(DATpin,LATSET);
   else PinSetBit(DATpin,LATCLR);
   PinSetBit(CLKpin,LATCLR);
   NOP();
   PinSetBit(CLKpin,LATSET);
   NOP();
 }
 PinSetBit(CSpin,LATSET);
}



void main(long long int *CS, long long int *CLK, long long int *DAT, long long int *ANA ){
 const char pe[]="Pin Error";
 if(CS==0 || CLK==0 || DAT==0)error((char *)pe);
 CSpin=*CS;
 CLKpin=*CLK;
 DATpin=*DAT;
 if(ANA!=0)ANApin=*ANA;
 else ANApin=0;
 AudioOutputVector=(unsigned int)&audio; //Set up the address for the audio interrupt output routine
}