Roland TB303 StepSequencer clone first draft notes...

examples/AcidStepSequencer/AcidStepSequencer.ino

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+#include "Arduino.h"
+#include <uClock.h>
+
+// Sequencer config
+#define STEP_MAX_SIZE      16
+#define SEQUENCER_MIN_BPM  50
+#define SEQUENCER_MAX_BPM  178
+#define NOTE_VELOCITY      90
+#define ACCENT_VELOCITY    110
+
+// Choose only 1 mode and comment the other.
+// OLD_SCHOOL_ACID_ACCENTED
+// a button/led extra hardware to control steps velocity using accent only
+// NEW_SCHOOL_VELOCITY_CONTROLLED
+// a 10k potentiomer extra hardware to freely control steps velocity
+#define OLD_SCHOOL_ACID_ACCENTED
+#define NEW_SCHOOL_FREE_VELOCITY
+
+typedef struct
+{
+  uint8_t note;
+  uint8_t velocity;
+  bool accent;
+  bool glide;
+  bool rest;
+} SEQUENCER_STEP_DATA;
+
+SEQUENCER_STEP_DATA _sequencer[STEP_MAX_SIZE];
+uint16_t _last_step = 0;
+
+// MIDI clock, start, stop, note on and note off byte definitions - based on MIDI 1.0 Standards.
+#define MIDI_CLOCK 0xF8
+#define MIDI_START 0xFA
+#define MIDI_STOP  0xFC
+#define NOTE_ON    0x90
+#define NOTE_OFF   0x80
+
+void sendMidiMessage(uint8_t command, uint8_t byte1, uint8_t byte2)
+{ 
+  // send midi message
+  Serial.write(command);
+  Serial.write(byte1);
+  Serial.write(byte2);
+}
+
+// The callback function wich will be called by uClock each Pulse of 16PPQN clock resolution.
+// At this resolution each call represents exactly one step.
+void ClockOut16PPQN(uint32_t * tick) 
+{
+  uint16_t step;
+  
+  // get actual step.
+  step = *tick % STEP_MAX_SIZE;
+  
+  // send note off for the last step note on if we had send it on last ClockOut16PPQN() call and if this step are not in glide mode also.
+  if ( _sequencer[_last_step].rest == false && _sequencer[_last_step].glide == false ) {
+    sendMidiMessage(NOTE_OFF, _sequencer[_last_step].note, 0);
+  }
+
+  // send note on only if this step are not in rest mode
+  if ( _sequencer[step].rest == false ) {
+    sendMidiMessage(NOTE_ON, _sequencer[step].note, _sequencer[step].velocity);
+  }
+
+  // time to let glide go away? be shure to send glided note off before the _last_step send his note off
+  // same note? do not send note off
+  if ( _sequencer[_last_step].glide == true && _sequencer[step].note != _sequencer[_last_step].note ) {
+    sendMidiMessage(NOTE_OFF, _sequencer[_last_step].note, 0);
+  }
+
+  _last_step = step;
+}
+
+// The callback function wich will be called by uClock each Pulse of 96PPQN clock resolution.
+void ClockOut96PPQN(uint32_t * tick) 
+{
+  // Send MIDI_CLOCK to external gears
+  Serial.write(MIDI_CLOCK);
+}
+
+// The callback function wich will be called when clock starts by using Clock.start() method.
+void onClockStart() 
+{
+  Serial.write(MIDI_START);
+}
+
+// The callback function wich will be called when clock stops by using Clock.stop() method.
+void onClockStop() 
+{
+  Serial.write(MIDI_STOP);
+}
+
+void setup() 
+{
+  // Initialize serial communication at 31250 bits per second, the default MIDI serial speed communication:
+  Serial.begin(31250);
+
+  // Inits the clock
+  uClock.init();
+  
+  // Set the callback function for the clock output to send MIDI Sync message.
+  uClock.setClock96PPQNOutput(ClockOut96PPQN);
+  
+  // Set the callback function for the step sequencer on 16ppqn
+  uClock.setClock16PPQNOutput(ClockOut16PPQN);  
+  
+  // Set the callback function for MIDI Start and Stop messages.
+  uClock.setOnClockStartOutput(onClockStart);  
+  uClock.setOnClockStopOutput(onClockStop);
+  
+  // Set the clock BPM to 126 BPM
+  uClock.setTempo(126);
+
+  // initing sequencer data
+  for ( uint16_t i = 0; i < STEP_MAX_SIZE; i++ ) {
+    _sequencer[i].note = 36;
+    _sequencer[i].velocity = NOTE_VELOCITY;
+    _sequencer[i].accent = false;
+    _sequencer[i].glide = false;
+    _sequencer[i].rest = false;
+  }
+
+  // Starts the clock, tick-tac-tick-tac...
+  uClock.start();
+}
+
+// User interaction goes here
+void loop() 
+{
+  // octave pot
+  // note pot
+  // tempo pot
+  // pattern step init pot
+  // pattern step size pot
+  // previous step button
+  // next step button
+  // rest button/led
+  // glide button/led
+  // accent button/led
+}