# KSynth Beginnings of a dual tone synthesizer for the Apple II All the code is in this README, since it's small enough to copy and paste into an emulator for now. The synth code itself ##Two Tone Generator## ``` 0300- A5 FD LDA $FD ; load second oscillator value into $FE 0302- 85 FE STA $FE ; 0304- A9 FF LDA #$FF ; load duration multiplier into $FC 0306- 85 FC STA $FC ; 0308- A4 FA LDY $FA ; load duration into Y 030A- A6 FB LDX $FB ; load oscillator into X 030C- CA DEX ; start countdown first oscillator, X 030D- EA NOP ; wait... 030E- EA NOP ; 030F- D0 05 BNE $0316 ; if X = 0, click. otherwise, skip 0311- 2C 30 C0 BIT $C030 ; click 0314- A6 FB LDX $FB ; reset X to beginning of countdown 0316- C6 FE DEC $FE ; countdown second oscillator, $FE 0318- EA NOP ; wait... 0319- EA NOP ; 031A- D0 07 BNE $0323 ; if $FE = 0, click. otherwise, skip 031C- 2C 30 C0 BIT $C030 ; click 031F- A5 FD LDA $FD ; reset $FE to beginning of countdown 0321- 85 FE STA $FE ; 0323- 88 DEY ; countdown duration 0324- D0 E6 BNE $030C ; if duration hasn't expired, return and count down oscillators 0326- A4 FA LDY $FA ; if duration has expired, reset duration 0328- C6 FC DEC $FC ; decrement duration multiplier 032A- D0 E0 BNE $030C ; if multiplier hasn't expired, return and count down oscillators 032C- 60 RTS ; all done 300: A5 FD 85 FE A9 FF 85 FC A4 FA A6 FB CA EA EA D0 05 8D 30 C0 A6 FB C6 FE EA EA D0 07 8D 30 C0 A5 FD 85 FE 88 D0 E6 A4 FA C6 FC D0 E0 60 ``` ##Player## ``` 0330- A9 00 LDA #$00 ; start at zero 0332- AA TAX ; X = 0; LOOP 0333- BD 00 10 LDA $1000,X ; load note duration 0336- F0 31 BEQ $0369 ; if note is 0 duration, end the song 0338- 85 FA STA $FA ; store duration at $FA 033A- E8 INX ; increment to note value 033B- BD 00 10 LDA $1000,X ; load note value 033E- 85 FB STA $FB ; store note value at $FB 0340- 85 FD STA $FD ; store note value at $FD 0342- C9 FF CMP #$FF ; if note value is FF, rest 0344- D0 06 BNE $034C ; skip over if !=FF 0346- 8D 1E 03 STA $031E ; change the $C030 click to $$FF30 0349- 8D 13 03 STA $0313 ; change the $C030 click to $$FF30 034C- C6 FD DEC $FD ; decrement $FD for That Karateka Sound™ 034E- 8A TXA ; put current note address in Accumulator 034F- 85 FF STA $FF ; store that in $FF 0351- 20 00 03 JSR $0300 ; play the actual note 0354- AD 13 03 LDA $0313 ; did we mess with the C030 click? 0357- C9 FF CMP #$FF ; if it's FF, we did. change it back. 0359- D0 08 BNE $0363 ; skip if !=FF 035B- A9 C0 LDA #$C0 ; set click points back to $c030 035D- 8D 1E 03 STA $031E ; 0360- 8D 13 03 STA $0313 ; 0363- E6 FF INC $FF ; increment to next note address 0365- A5 FF LDA $FF ; load Accumulator with next note address 0367- D0 C9 BNE $0332 ; branch to LOOP 0369- 60 RTS ; 330: A9 00 AA BD 00 10 F0 31 85 FA E8 BD 00 10 85 FB 85 FD C9 FF D0 06 8D 1E 03 8D 13 03 C6 FD 8A 85 FF 20 00 03 AD 13 03 C9 FF D0 08 A9 C0 8D 1E 03 8D 13 03 E6 FF A5 FF D0 C9 60 ``` ##Creating Music## Music is stored in the following format, beginning (by default) at $1000. Starting address = A ($1000) A+0 = duration _e.g. FF = 1.63 seconds_ A+1 = note _e.g. 59 = 440Hz A_ per chart at [https://www.seventhstring.com/resources/notefrequencies.html] NOTE | C | C# | D | Eb | E | F | F# | G | G# | A | Bb | B | |-----| ------ | ------ | ------ | ------ | ------ | ------ | ------ | ------ | ------ | ------ | ------ | ------ | FREQ | | | | 155.6 | 164.8 | 174.6 | 185.0 | 196.0 | 207.7 | 220.0 | 233.1 | 246.9 BYTE | | | | FC | EF | E1 | D5 | C9 | BD | B3 | A9 | 9F FREQ | 261.6 | 277.2 | 293.7 | 311.1 | 329.6 | 349.2 | 370.0 | 392.0 | 415.3 | 440.0 | 466.2 | 493.9 BYTE | 96 | 8E | 86 | 7E | 77 | 71 | 6A | 64 | 5E | 59 | 54 | 4F FREQ | 523.3 | 554.4 | 587.3 | 622.3 | 659.3 | 698.5 | 740.0 | 784.0 | 830.6 | 880.0 | 932.3 | 987.8 BYTE | 4B | 47 | 43 | 3F | 3C | 38 | 35 | 32 | 2F | 2D | 2A | 27 FREQ | 1047 | 1109 | 1175 | 1245 | 1319 | 1397 | 1480 | 1568 | 1661 | 1760 | 1865 | 1976 BYTE | 25 | 23 | 21 | 1F | 1E | 1C | 1A | 19 | 17 | 16 | 15 | 13 ##Bb scale:## ``` 1000: 20 A9 20 96 20 86 20 7E 20 71 20 64 20 59 20 54 20 59 20 64 20 71 20 7E 20 86 20 96 FF A9 FF FF 10 A9 10 86 10 71 10 54 10 71 10 86 FF A9 00 ``` ##Karateka victory:## ``` 1000: 10 a8 20 FF 8 c7 5 FF 10 a8 15 FF 25 7e 20 FF 10 63 08 FF 80 63 00 00 ``` and, of course, the requisite ##Daisy Bell (Bicycle Built For Two)## ``` 1000: 30 71 30 86 30 A9 30 e1 10 C9 10 B3 10 A9 20 C9 10 A9 60 e1 30 96 30 71 30 86 30 A9 10 C9 10 B3 10 A9 20 96 10 86 40 96 10 FF 10 86 10 77 10 86 1030: 10 96 20 71 10 86 10 96 40 A9 10 96 20 86 10 A9 20 C9 10 A9 10 C9 40 e1 10 E1 20 A9 10 86 10 96 20 FF 20 A9 10 86 10 96 10 FF 5 86 5 77 10 71 10 86 10 A9 20 96 10 e1 40 A9 00 00 ``` ##MIDI Translation## Using the above table as a starting point, a MIDI lookup table can be created. MIDI addresses up to 127 notes, from a C three octaves below Bass Clef, up to a G 9 octaves above. [http://www.midikits.net/midi_analyser/midi_note_numbers_for_octaves.htm] 440hz A is note 69 in MIDI, so byte 69 (0x45) of the KSYNTH lookup table. By shifting 12 bytes up or down (one octave), a song's range can be easily be changed to fit in KSYNTH's limited range. ``` C C# D D# E F F# G G# A A# B 0 00 00 00 00 00 00 00 00 00 00 00 00 1 00 00 00 00 00 00 00 00 00 00 00 00 2 00 00 00 00 00 00 00 00 00 00 00 00 3 00 00 00 00 00 00 00 00 00 00 00 00 4 00 00 00 FC EF E1 D5 C9 BD B3 A9 9F 5 96 8E 86 7E 77 71 6A 64 5E 59 54 4F 6 4B 47 43 3F 3C 38 35 32 2F 2D 2A 27 7 25 23 21 1F 1E 1C 1A 19 17 16 15 13 8 00 00 00 00 00 00 00 00 00 00 00 00 9 00 00 00 00 00 00 00 00 1133: FC EF E1 D5 C9 BD B3 A9 9F 96 8E 86 7E 77 71 6A 64 5E 59 54 4F 4B 47 43 3F 3C 38 35 32 2F 2D 2A 27 25 23 21 1F 1E 1C 1A 19 17 16 15 13 ``` ##MIDI-like Player## _assumes song src at $1000_ _assumes lookup table src at $1100_ ``` 0330- A9 00 LDA #$00 ; start at zero 0332- AA TAX ; X = 0; LOOP 0333- BD 00 10 LDA $1000,X ; load note duration 0336- F0 31 BEQ $0369 ; if note is 0 duration, end the song 0338- 85 FA STA $FA ; store duration at $FA 033A- E8 INX ; increment pointer to note value 033B- BD 00 10 LDA $1000,X ; load note MIDI-style value TAY ; lookup note loop value from lookup table LDA $1100,Y ; 033E- 85 FB STA $FB ; store note value at $FB 0340- 85 FD STA $FD ; store note value at $FD 0342- C9 FF CMP #$FF ; if note value is FF, rest 0344- D0 06 BNE $034C ; skip over if !=FF 0346- 8D 1E 03 STA $031E ; change the $C030 click to BIT $FF30 0349- 8D 13 03 STA $0313 ; change the $C030 click to BIT $FF30 034C- C6 FD DEC $FD ; decrement $FD for That Karateka Sound™ 034E- 8A TXA ; put current note pointer in Accumulator 034F- 85 FF STA $FF ; store that in $FF 0351- 20 00 03 JSR $0300 ; play the actual note 0354- AD 13 03 LDA $0313 ; did we mess with the C030 click? 0357- C9 FF CMP #$FF ; if it's FF, we did. change it back. 0359- D0 08 BNE $0363 ; skip if !=FF 035B- A9 C0 LDA #$C0 ; set click points back to $c030 035D- 8D 1E 03 STA $031E ; 0360- 8D 13 03 STA $0313 ; 0363- E6 FF INC $FF ; increment to next note address 0365- A5 FF LDA $FF ; load Accumulator with next note address 0367- D0 C9 BNE $0332 ; branch to LOOP 0369- 60 RTS ; 330: A9 00 AA BD 00 10 F0 31 85 FA E8 BD 00 10 A8 B9 00 11 85 FB 85 FD C9 FF D0 06 8D 1E 03 8D 13 03 C6 FD 8A 85 FF 20 00 03 AD 13 03 C9 FF D0 08 A9 C0 8D 1E 03 8D 13 03 E6 FF A5 FF D0 C9 60 This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 United States License. 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