# 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. There is also a Merlin32 compatible source file, ksynth.s, with comments and equivalents to make it more relocatable. The included DSK file contains the following files: - *KSYNTH*: The core sound generation routine - *KSYNTH.PLAYER*: Basic player routine. Assumes SONG bytes starting at $1000 - *BFLATSCALE.SONG*: B-Flat scale - *VICTORY.SONG*: "Victory" tune from Karateka - *DAISYBELL.SONG*: "Bicylce Built for Two" AKA "Daisy Bell" - *DAISYBELL.MIDI*: "Bicylce Built for Two" AKA "Daisy Bell" in MIDI-like format for KSYNTH.MIDI - *KSYNTH.MIDI*: MIDI-style KSYNTH player routine. Looks up notes from MIDI.LOOKUP instead of raw cycle counts. - *MIDI.LOOKUP*: Lookup table of notes to cycle counts for MIDI style player. - *RANDOMNOTES*: A routine to play random tones with the KSYNTH routine. - *MIDI.LOOKUP2*: Alternate MIDI lookup table that covers larger range of tones - *TWOTONE.PLAYER*: Slightly different MIDI-style player. Plays arbitrary two-note combinations. To do: Add more MIDI example songs. 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. ``` notes and octaves 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 bytes $30 00 00 00 FC EF E1 D5 C9 BD B3 A9 9F 96 8E 86 7E $40 77 71 6A 64 5E 59 54 4F 4B 47 43 3F 3C 38 35 32 $50 2F 2D 2A 27 25 23 21 1F 1E 1C 1A 19 17 16 15 13 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 ``` ##Daisy Bell (Bicycle Built For Two) MIDI style## 1000: 30 41 30 3E 30 3A 30 35 10 37 10 39 10 3A 20 37 10 3A 60 35 30 3C 30 41 30 3E 30 3A 10 37 10 39 10 3A 20 3C 10 3E 40 3C 10 FF 10 3E 10 40 10 3E 1030: 10 3C 20 41 10 3E 10 3C 40 3A 10 3C 20 3E 10 3A 20 37 10 3A 10 37 40 35 10 35 20 3A 10 3E 10 3C 20 FF 20 3A 10 3E 10 3C 10 FF 5 3E 5 40 10 41 10 3E 10 3A 20 3C 10 35 40 3A 00 00 ##KSYNTH.MIDI: 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 35 BEQ $036D ; 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 033E- A8 TAY ; lookup note loop value from lookup table 033F- B9 00 11 LDA $1100,Y ; 0342- 85 FB STA $FB ; store note value at $FB 0344- 85 FD STA $FD ; store note value at $FD 0346- C9 FF CMP #$FF ; if note value is FF, rest 0348- D0 06 BNE $0350 ; skip over if !=FF 034A- 8D 1E 03 STA $031E ; change the $C030 click to BIT $FF30 034D- 8D 13 03 STA $0313 ; change the $C030 click to BIT $FF30 0350- C6 FD DEC $FD ; decrement $FD for That Karateka Sound™ 0352- 8A TXA ; put current note pointer in Accumulator 0353- 85 FF STA $FF ; store that in $FF 0355- 20 00 03 JSR $0300 ; play the actual note 0358- AD 13 03 LDA $0313 ; did we mess with the C030 click? 035B- C9 FF CMP #$FF ; if it's FF, we did. change it back. 035D- D0 08 BNE $0367 ; skip if !=FF 035F- A9 C0 LDA #$C0 ; set click points back to $c030 0361- 8D 1E 03 STA $031E ; 0364- 8D 13 03 STA $0313 ; 0367- E6 FF INC $FF ; increment to next note address 0369- A5 FF LDA $FF ; load Accumulator with next note address 036B- D0 C5 BNE $0332 ; branch to LOOP 036D- 60 RTS ; 330: A9 00 AA BD 00 10 F0 35 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 C5 60 This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 United States License. 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