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sequencer.c
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sequencer.c
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/*
* K2579 Step Sequencer - Sequencer Core
*
* Copyright 2011: Kilpatrick Audio
* Written by: Andrew Kilpatrick
*
* - clock divide behaviour:
* - all song position, gate and clock functions are based on 24ppq
* - steps are taken based on the clock divider
*
*/
#include <plib.h>
#include <stdlib.h>
#include <stdio.h>
#include "sequencer.h"
#include "song.h"
#include "midi.h"
#include "cv_output.h"
#include "analog_input.h"
#include "clock.h"
#include "sysconfig.h"
#include "gui.h"
#include "seq_midi.h"
#include "scale.h"
#include "panel.h"
#define STEP_INVALID 127
// clock control
#define NOTE_KILL_TIME_RUN 39063 // ~10s at 256us per count
#define NOTE_KILL_TIME_STOP 796 // 0.500ms at 256us per count
#define MOD_LED_TIMEOUT 2 // 32ms
unsigned int clock_tick_count; // clock tick count
unsigned char clock_div_count; // the current clock divide counter
int note_kill_timeout; // the note timeout counter - for stopped clock
// sequencer internal
#define MIDI_NOTE_OFFSET 24
unsigned char next_cued_seq; // the next seq to play or 255 if invalid
// these are used for display because the step is updated after each step is started
unsigned char current_seq_playing; // the current sequence playing now
unsigned char current_step_index_playing; // the current step index playing now
// current playback variables
unsigned char current_seq; // the currently playing sequence
unsigned char current_loop_count; // the number of loops taken
char current_step_count; // current step count based on the dir and length - counts from 0 to len
unsigned char current_pingpong; // the current ping pong count
unsigned char current_note[2]; // current note or 255
unsigned char gate_time_count[2]; // the current gate time counted
// control overrides
unsigned char control_start_override; // 0-15 start override or 255 if disabled
unsigned char control_len_override; // 0-15 length override or 255 if disabled
unsigned char control_gate_override[2]; // 1-48 length override or 255 disabled
unsigned char control_dir_override; // 1 = override or 255 if disabled
char control_offset_override[2]; // -12 to +12 overrides the offset
unsigned char control_run_override; // 1 = run stopped or 255 if disabled
unsigned char control_key_map_override; // 1 = swapped, 255 = normal
// local functions
// start a note
void sequencer_start_note(unsigned char part, unsigned char note);
// stop a note
void sequencer_stop_note(unsigned char part);
// the clock has changed
void sequencer_clock_changed(void);
// advance the sequencer 1 step
void sequencer_advance_step(void);
// the end of a loop is reached - figure out what to do next
void sequencer_loop_end(unsigned char len, unsigned char dir);
// compute and return the current step based on dir, len, etc.
char sequencer_compute_current_step(void);
// reset song position
void sequencer_reset_song_pos(void);
// initialize the sequencer
void sequencer_init(void) {
// clock control
clock_tick_count = 0;
note_kill_timeout = 0;
// sequencer internal
sequencer_reset_song_pos();
sequencer_control_restore();
}
// run the sequencer task every 256us
void sequencer_task(void) {
// note kill
if(note_kill_timeout) {
note_kill_timeout --;
if(note_kill_timeout == 0) {
sequencer_stop_note(0);
sequencer_stop_note(1);
}
}
}
// start a note
void sequencer_start_note(unsigned char part, unsigned char note) {
unsigned char not;
if(part > 1) return;
if(control_offset_override[part]) {
not = note + 12 + control_offset_override[part]; // 12-60 normal range
}
else {
not = note + 12 + song_get_offset(current_seq, part); // 12-60 normal range
}
if(not < 12 || not > 115) return;
// send MIDI note
current_note[part] = not;
gate_time_count[part] = 0;
_midi_tx_note_on(seq_midi_get_channel(part), current_note[part] + MIDI_NOTE_OFFSET, 100);
// control analog output
cv_output_note_on(part, current_note[part]);
// reset the note timeout
if(clock_get_song_playing()) note_kill_timeout = NOTE_KILL_TIME_RUN;
else note_kill_timeout = NOTE_KILL_TIME_STOP;
}
// stop a note
void sequencer_stop_note(unsigned char part) {
if(part > 1) return;
if(current_note[part] == 255) return;
// send MIDI note
_midi_tx_note_off(seq_midi_get_channel(part), current_note[part] + MIDI_NOTE_OFFSET);
current_note[part] = 255;
// control analog output
cv_output_note_off(part);
}
// the clock has changed
void sequencer_clock_changed(void) {
int i;
unsigned char gate;
// gate time
for(i = 0; i < 2; i ++) {
if(current_note[i]) {
gate_time_count[i] ++;
gate = song_get_gate(current_seq, i);
if(control_gate_override[i] != 255) gate = control_gate_override[i];
if(gate_time_count[i] >= gate) {
sequencer_stop_note(i);
}
}
}
// next step
if(clock_div_count == 0) {
int note;
char step;
// get the current step based on the start, len and random
step = sequencer_compute_current_step();
// control each note
for(i = 0; i < 2; i ++) {
note = song_get_note(current_seq, i, step);
if(note == SONG_STEP_RAND) {
note = song_get_rand_note();
}
note = scale_span_adjust(note, song_get_span(current_seq, i));
note = scale_quantize(note, song_get_scale(current_seq, i));
if(note == SONG_STEP_REST) {
sequencer_stop_note(i);
}
else if(note == SONG_STEP_NONE) {
// do nothing
}
else {
sequencer_stop_note(i);
sequencer_start_note(i, note);
}
}
// update the display positions based on the step just played
current_seq_playing = current_seq;
current_step_index_playing = step;
gui_playback_updated();
// advance the sequencer for the next step
sequencer_advance_step();
}
clock_div_count ++;
// step time override
unsigned char step_len = song_get_step_len(current_seq, current_step_index_playing);
// a step len of >0 means use it for the clock div count
if(step_len) {
if(clock_div_count >= step_len) {
clock_div_count = 0;
}
}
// otherwise use the master clock div
else if(clock_div_count >= sysconfig_get_clock_div()) {
clock_div_count = 0;
}
note_kill_timeout = NOTE_KILL_TIME_RUN;
}
// advance the sequencer 1 step
void sequencer_advance_step(void) {
// length
unsigned char len = song_get_seq_len(current_seq);
if(control_len_override != 255) {
len = control_len_override;
}
// direction
unsigned char dir = song_get_seq_dir(current_seq);
if(control_dir_override == 1) {
// flip directions for forward / backward
if(dir == SONG_DIR_FWD) dir = SONG_DIR_BACK;
else if(dir == SONG_DIR_BACK) dir = SONG_DIR_FWD;
}
// the current step has not yet been initialized
if(current_step_count == STEP_INVALID) {
sequencer_loop_end(len, dir);
return;
}
// pingpong
if(dir == SONG_DIR_PONG) {
// ponging (backwards)
if(current_pingpong & 0x01) {
current_step_count --;
// start is reached
if(current_step_count <= 0) {
current_step_count = 0;
current_pingpong = 0;
sequencer_loop_end(len, dir);
}
}
// pinging (forwards)
else {
current_step_count ++;
// len is reached
if(current_step_count >= len - 1) {
current_step_count = len - 1;
current_pingpong = 1;
sequencer_loop_end(len, dir);
}
}
}
// go forwards / randomly
else if(dir == SONG_DIR_FWD || dir == SONG_DIR_RAND) {
current_step_count ++;
// len is reached
if(current_step_count > (len - 1)) {
current_step_count = 0;
sequencer_loop_end(len, dir);
}
}
// go backwards
else if(dir == SONG_DIR_BACK) {
current_step_count --;
// start is reached
if(current_step_count < 0) {
current_step_count = len - 1;
sequencer_loop_end(len, dir);
}
}
}
// the end of a loop is reached - figure out what to do next
void sequencer_loop_end(unsigned char len, unsigned char dir) {
// step is invalid from the reset - cause sequence to reload
if(current_step_count == STEP_INVALID) {
current_seq = 254;
}
// we've reached a loop end
else {
current_loop_count ++;
// number of loops is exceeded
if(current_loop_count > song_get_seq_loop(current_seq) && next_cued_seq == 255) {
next_cued_seq = song_get_seq_next(current_seq);
}
}
// if the cued seq is not the one we're on
if((next_cued_seq != 255) & (next_cued_seq != current_seq)) {
current_seq = next_cued_seq;
current_pingpong = 0;
current_loop_count = 0;
// length
unsigned char new_len = song_get_seq_len(current_seq);
if(control_len_override != 255) {
new_len = control_len_override;
}
// direction
unsigned char new_dir = song_get_seq_dir(current_seq);
if(control_dir_override == 1) {
// flip directions for forward / backward
if(new_dir == SONG_DIR_FWD) new_dir = SONG_DIR_BACK;
else if(new_dir == SONG_DIR_BACK) new_dir = SONG_DIR_FWD;
}
// for backwards we start on the last step
if(new_dir == SONG_DIR_BACK) {
current_step_count = new_len - 1;
}
// for forwards we start on step 0
else {
current_step_count = 0;
}
}
next_cued_seq = 255;
}
// compute and return the current step based on dir, len, etc.
char sequencer_compute_current_step(void) {
char temp;
// start
unsigned char new_start = song_get_seq_start(current_seq);
if(control_start_override != 255) {
new_start = control_start_override;
}
// go randomly
if(song_get_seq_dir(current_seq) == SONG_DIR_RAND) {
// length
unsigned char new_len = song_get_seq_len(current_seq);
if(control_len_override != 255) {
new_len = control_len_override;
}
temp = ((rand() >> 4) % new_len) + new_start;
}
// go sequentially
else {
temp = current_step_count + new_start;
}
// clamp the step index range because it wraps around for start/len offsets
if(temp > (SONG_NUM_STEPS - 1)) temp -= SONG_NUM_STEPS;
else if(temp < 0) temp += SONG_NUM_STEPS;
return temp;
}
// reset song position
void sequencer_reset_song_pos(void) {
clock_tick_count = 0; // reset the song position
clock_div_count = 0;
// reset the sequence only
if(sysconfig_get_reset_mode() == SYSCONFIG_RESET_MODE_SEQ) {
next_cued_seq = current_seq;
}
// reset the entire song
else {
next_cued_seq = 0; // next cued sequence is 0
}
current_seq_playing = next_cued_seq;
current_step_count = STEP_INVALID; // invalidate the current position
current_loop_count = 0;
current_pingpong = 0;
sequencer_advance_step();
current_step_index_playing = sequencer_compute_current_step();
current_note[0] = 255; // disabled
current_note[1] = 255; // disabled
gate_time_count[0] = 0;
gate_time_count[1] = 0;
gui_playback_updated();
}
//
// MIDI / analog clock handlers
//
// set song position
void sequencer_midi_song_pos(unsigned int pos) {
unsigned char clock_div = sysconfig_get_clock_div();
_midi_tx_song_position(pos); // send song position pointer
// calculate the current position
sequencer_reset_song_pos(); // reset the song
clock_tick_count = pos * 6; // calculate the desired clock tick offset
unsigned int advance_tick_count = 0;
unsigned char step_len = 0;
unsigned char step = 0;
while(1) {
// get the current step based on the start, len and random
step = sequencer_compute_current_step();
step_len = song_get_step_len(current_seq, step);
// step length is default (clock_div)
if(step_len == 0) {
step_len = clock_div;
}
// if we're past the SPP then break
if(advance_tick_count + step_len > clock_tick_count) break;
// add the step length
advance_tick_count += step_len;
sequencer_advance_step(); // move to the next step
ClearWDT();
}
// deal with remainder
clock_div_count = clock_tick_count - advance_tick_count;
current_seq_playing = current_seq;
current_step_index_playing = sequencer_compute_current_step();
gui_playback_updated();
}
//
// MIDI/analog control handlers
//
// clock pulse was received
void sequencer_clock_tick(void) {
if(control_run_override == 1) return;
sequencer_clock_changed();
clock_tick_count ++;
}
// start song at beginning
void sequencer_clock_start(void) {
sequencer_stop_note(0);
sequencer_stop_note(1);
sequencer_reset_song_pos();
}
// stop song
void sequencer_clock_stop(void) {
sequencer_stop_note(0);
sequencer_stop_note(1);
_midi_tx_control_change(seq_midi_get_channel(0), 123, 0);
_midi_tx_control_change(seq_midi_get_channel(1), 123, 0);
}
// get the current clock div count
unsigned char sequencer_get_clock_div_count(void) {
return clock_div_count;
}
//
// external control of sequence
//
// MIDI key trigger
void sequencer_key_trigger(unsigned char seq) {
if(seq > SONG_NUM_SEQ) return;
sequencer_set_next_seq(seq);
clock_run_command(); // make sure we start if we're stopped
}
// MIDI key transpose
void sequencer_key_transpose(char transpose) {
unsigned char assign = sysconfig_get_key_transpose();
if(transpose < -12 || transpose > 12) return;
if(assign == SYSCONFIG_KEY_TRANSPOSE12) {
control_offset_override[0] = transpose;
control_offset_override[1] = transpose;
}
else if(assign == SYSCONFIG_KEY_TRANSPOSE1) {
control_offset_override[0] = transpose;
}
else if(assign == SYSCONFIG_KEY_TRANSPOSE2) {
control_offset_override[1] = transpose;
}
}
// MIDI/analog control change was received
// send values from 0-127 to here
void sequencer_control_change(unsigned char mod, unsigned char value) {
if(value > 127) return;
// next sequence
if(mod == SYSCONFIG_MOD_NEXT_SEQ) {
sequencer_set_next_seq(value >> 3);
}
// sequence start
else if(mod == SYSCONFIG_MOD_SEQ_START) {
control_start_override = (value >> 3);
}
// sequence len
else if(mod == SYSCONFIG_MOD_SEQ_LEN) {
control_len_override = (value >> 3) + 1;
}
// sequence run/stop
else if(mod == SYSCONFIG_MOD_RUN_STOP) {
// stop
if(value < 64) {
if(control_run_override == 255) {
clock_stop_command();
control_run_override = 1;
}
}
else {
if(control_run_override == 1) {
clock_run_command();
control_run_override = 255;
}
}
}
// gate 1 length
else if(mod == SYSCONFIG_MOD_GATE1) {
control_gate_override[0] = (value >> 2) + 1;
}
// gate 2 length
else if(mod == SYSCONFIG_MOD_GATE2) {
control_gate_override[1] = (value >> 2) + 1;
}
// dir
else if(mod == SYSCONFIG_MOD_SEQ_DIR) {
if(value < 64) control_dir_override = 255;
else control_dir_override = 1;
}
// key map - this is special and not part of the normal group
else if(mod == SYSCONFIG_MOD_KEY_MAP) {
if(value < 64) control_key_map_override = 255;
else control_key_map_override = 1;
}
// not recognized mod
else {
return;
}
// blink the mod led
panel_set_mod_led(MOD_LED_TIMEOUT);
// send event about the updated status
gui_control_override_updated();
}
// get a control override value
// returns values in the local range
unsigned char sequencer_get_control_override(unsigned char mod) {
// next sequence
if(mod == SYSCONFIG_MOD_NEXT_SEQ) {
// not supported
}
// sequence start
else if(mod == SYSCONFIG_MOD_SEQ_START) {
if(control_start_override != 255) {
return control_start_override;
}
}
// sequence len
else if(mod == SYSCONFIG_MOD_SEQ_LEN) {
if(control_len_override != 255) {
return control_len_override;
}
}
// sequence run/stop
else if(mod == SYSCONFIG_MOD_RUN_STOP) {
if(control_run_override != 255) {
return 0;
}
}
// gate 1 length
else if(mod == SYSCONFIG_MOD_GATE1) {
if(control_gate_override[0]) {
return control_gate_override[0];
}
}
// gate 2 length
else if(mod == SYSCONFIG_MOD_GATE2) {
if(control_gate_override[1]) {
return control_gate_override[1];
}
}
// dir
else if(mod == SYSCONFIG_MOD_SEQ_DIR) {
if(control_dir_override != 255) {
return control_dir_override;
}
}
// keymap
else if(mod == SYSCONFIG_MOD_KEY_MAP) {
if(control_key_map_override != 255) {
return control_key_map_override;
}
}
return 255;
}
// restore the current CC / key overrides to the default value
void sequencer_control_restore(void) {
control_start_override = 255; // disabled
control_len_override = 255; // disabled
control_gate_override[0] = 255; // disabled
control_gate_override[1] = 255; // disabled
control_dir_override = 255; // disabled
control_offset_override[0] = 0; // disabled
control_offset_override[1] = 0; // disabled
control_run_override = 255; // disabled
control_key_map_override = 255; // disabled
gui_control_override_updated();
}
// restore the run/stop override to panel control
void sequencer_control_run_stop_restore(void) {
control_run_override = 255; // disabled
gui_control_override_updated();
}
// get the current sequence
unsigned char sequencer_get_current_seq(void) {
return current_seq_playing;
}
// set the current sequence
void sequencer_set_next_seq(unsigned char seq) {
if(seq > (SONG_NUM_SEQ - 1)) return;
// if the song is playing, don't interrupt the current loop pass
if(clock_get_song_playing()) {
next_cued_seq = seq; // cue up for the next pass
}
// otherwise reset everything and set it immediately
else {
sequencer_reset_song_pos();
// if we have to force another sequence to change
if(seq != current_seq) {
next_cued_seq = seq;
current_step_count = STEP_INVALID; // invalidate the current position
sequencer_advance_step();
}
// force correct display
current_seq_playing = current_seq;
current_step_index_playing = sequencer_compute_current_step();
gui_playback_updated();
}
}
// get the current sequence step index
unsigned char sequencer_get_current_step_index(void) {
return current_step_index_playing;
}
// set a note for preview
void sequencer_play_audition_note(unsigned char part, unsigned char note) {
if(part > 1) return;
sequencer_stop_note(part);
sequencer_start_note(part, note);
}
// calibrate the CV outputs
void sequencer_cv_cal_start(void) {
clock_stop_command();
}
// set a CV calibration voltage
void sequencer_cv_set_cal(unsigned char part, char octave) {
unsigned char note;
if(part > 1) return;
if(octave > 6) return;
note = octave * 12;
// don't multi-trigger
if(current_note[part] == note) return;
// turn off notes if already playing
if(current_note[part] != 255) {
_midi_tx_note_off(seq_midi_get_channel(part), current_note[part] + MIDI_NOTE_OFFSET);
current_note[part] = 255;
}
// send MIDI note
current_note[part] = note;
gate_time_count[part] = 0;
_midi_tx_note_on(seq_midi_get_channel(part), current_note[part] + MIDI_NOTE_OFFSET, 100);
// control analog output
cv_output_note_on(part, current_note[part]);
// reset the note timeout
if(clock_get_song_playing()) note_kill_timeout = NOTE_KILL_TIME_RUN;
else note_kill_timeout = NOTE_KILL_TIME_STOP;
}
// song is loaded - need to reset the start position
void sequencer_new_song_loaded(void) {
// clock control
clock_tick_count = 0;
note_kill_timeout = 0;
// sequencer internal
sequencer_reset_song_pos();
sequencer_control_restore();
}