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uClock
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added clock decimal precision(128.5bpm). added a buffer for average interval tick reading on getTempo() to smooth slave tempo retrive. Revised Teensy USB midi clock monitor

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pull/7/head 0.9.4
midilab 4 years ago
parent 2f70ed8b82
commit c71e55615c
4 changed files with 72 additions and 34 deletions
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  1. 43
      examples/TeensyUsbSlaveMidiClockMonitor/TeensyUsbSlaveMidiClockMonitor.ino
  2. 2
      library.properties
  3. 42
      src/uClock.cpp
  4. 19
      src/uClock.h

43
examples/TeensyUsbSlaveMidiClockMonitor/TeensyUsbSlaveMidiClockMonitor.ino
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@ -4,15 +4,21 @@
* MIDI hid compilant slave clock box with
* monitor support using oled displays
*
* Making use of a 250 usceconds timer to
* Making use of a 16 usceconds timer to
* handle MIDI input to avoid jitter on clock
*
* You need the following libraries to make it work
* - u8g2
* - uClock
*
* This example make use of drift values (1, 4)
* respectively for internal and external drift reference.
* This example was tested on a macbook
* running ableton live 9 as master clock
*
* This example code is in the public domain.
*/
#include <U8x8lib.h>
//
@ -28,8 +34,8 @@ IntervalTimer teensyTimer;
#define MIDI_START 0xFA
#define MIDI_STOP 0xFC
char bpm_str[3];
uint16_t bpm = 126;
char bpm_str[4];
float bpm = 126;
uint8_t bpm_blink_timer = 1;
uint8_t clock_state = 1;
@ -60,6 +66,7 @@ void onClockStart() {
void onClockStop() {
usbMIDI.sendRealTime(MIDI_STOP);
digitalWrite(LED_BUILTIN, LOW);
}
// External clock handlers
@ -105,15 +112,16 @@ void setup() {
//
// Setup our clock system
// drift for USB Teensy
uClock.setDrift(1);
uClock.setDrift(1, 4);
uClock.init();
uClock.setClock96PPQNOutput(ClockOut96PPQN);
// For MIDI Sync Start and Stop
uClock.setOnClockStartOutput(onClockStart);
uClock.setOnClockStopOutput(onClockStop);
uClock.setMode(uClock.EXTERNAL_CLOCK);
// make use of 250us timer to handle midi input sync
teensyTimer.begin(handleMidiInput, 250);
// make use of 16us timer to handle midi input sync
teensyTimer.begin(handleMidiInput, 16);
teensyTimer.priority(80);
}
void handleMidiInput() {
@ -121,12 +129,27 @@ void handleMidiInput() {
}
}
void printBpm(float _bpm, uint8_t col, uint8_t line) {
int b = (int)_bpm;
int c = (int)((_bpm-b)*10);
itoa(b, bpm_str, 10);
if (b > 99) {
u8x8->drawUTF8(col, line, bpm_str);
} else {
bpm_str[2] = "\0";
u8x8->drawUTF8(col, line, " ");
u8x8->drawUTF8(col+1, line, bpm_str);
}
u8x8->drawUTF8(col+3, line, ".");
itoa(c, bpm_str, 10);
u8x8->drawUTF8(col+4, line, bpm_str);
u8x8->drawUTF8(col+5, line, "bpm");
}
void loop() {
if (bpm != uClock.getTempo()) {
bpm = uClock.getTempo();
itoa(bpm, bpm_str, 10);
u8x8->drawUTF8(10, 7, bpm_str);
u8x8->drawUTF8(13, 7, "bpm");
printBpm(bpm, 8, 7);
}
if (clock_state != uClock.state) {
clock_state = uClock.state;

2
library.properties
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@ -1,5 +1,5 @@
name=uClock
version=0.9.2
version=0.9.4
author=Romulo Silva <contact@midilab.co>, Manuel Odendahl <wesen@ruinwesen.com>
maintainer=Romulo Silva <contact@midilab.co>
sentence=BPM clock generator for Arduino and Teensy boards

42
src/uClock.cpp
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@ -3,7 +3,7 @@
* Project BPM clock generator for Arduino
* @brief A Library to implement BPM clock tick calls using hardware timer1 interruption. Tested on ATmega168/328, ATmega16u4/32u4 and ATmega2560.
* Derived work from mididuino MidiClock class. (c) 2008 - 2011 - Manuel Odendahl - wesen@ruinwesen.com
* @version 0.9.3
* @version 0.9.4
* @author Romulo Silva
* @date 08/21/2020
* @license MIT - (c) 2020 - Romulo Silva - contact@midilab.co
@ -39,13 +39,14 @@ IntervalTimer _teensyTimer;
void teensyInterrupt();
void initTeensyTimer()
{
_teensyTimer.begin(teensyInterrupt, 16);
// 62500Hz
_teensyTimer.begin(teensyInterrupt, 16);
// Set the interrupt priority level, controlling which other interrupts
// this timer is allowed to interrupt. Lower numbers are higher priority,
// with 0 the highest and 255 the lowest. Most other interrupts default to 128.
// As a general guideline, interrupt routines that run longer should be given
// lower priority (higher numerical values).
//_teensyTimer.priority(128);
_teensyTimer.priority(0);
}
#else
void initArduinoTimer()
@ -103,6 +104,7 @@ uClockClass::uClockClass()
// 1 is good on teensy lc usb midi
internal_drift = 11;
external_drift = 11;
tempo = 120;
pll_x = 220;
start_timer = 0;
last_interval = 0;
@ -116,11 +118,13 @@ uClockClass::uClockClass()
onClock16PPQNCallback = NULL;
onClockStartCallback = NULL;
onClockStopCallback = NULL;
// first interval calculus
setTempo(tempo);
}
void uClockClass::init()
{
setTempo(120);
initWorkTimer();
}
@ -161,7 +165,7 @@ void uClockClass::pause()
}
}
void uClockClass::setTempo(uint16_t bpm)
void uClockClass::setTempo(float bpm)
{
if (mode == EXTERNAL_CLOCK) {
return;
@ -177,20 +181,27 @@ void uClockClass::setTempo(uint16_t bpm)
tempo = bpm;
ATOMIC(
ATOMIC(
interval = (uint16_t)((156250.0 / tempo) - internal_drift);
//interval = 62500 / (tempo * 24 / 60) - internal_drift;
interval = (uint16_t)(156250 / tempo) - internal_drift;
)
}
uint16_t uClockClass::getTempo()
float uClockClass::getTempo()
{
if (mode == EXTERNAL_CLOCK) {
uint16_t external_interval;
ATOMIC(
external_interval = interval;
)
tempo = (156250 / (external_interval + external_drift));
uint32_t acc = 0;
uint8_t acc_counter = 0;
for (uint8_t i=0; i < EXT_INTERVAL_BUFFER_SIZE; i++) {
if ( ext_interval_buffer[i] != 0) {
acc += ext_interval_buffer[i];
++acc_counter;
}
}
if (acc != 0) {
// get average interval, because MIDI sync world is a wild place...
tempo = (float)(156250.0 / ((acc / acc_counter) + external_drift));
}
}
return tempo;
}
@ -232,6 +243,8 @@ void uClockClass::resetCounters()
mod6_counter = 0;
indiv96th_counter = 0;
inmod6_counter = 0;
ext_interval_buffer[EXT_INTERVAL_BUFFER_SIZE] = {0};
ext_interval_idx = 0;
}
// TODO: Tap stuff
@ -273,6 +286,9 @@ void uClockClass::handleExternalClock()
} else {
interval = (((uint32_t)interval * (uint32_t)pll_x) + (uint32_t)(256 - pll_x) * (uint32_t)last_interval) >> 8;
}
// accumulate interval incomming ticks data(for a better getTempo stability over bad clocks)
ext_interval_buffer[ext_interval_idx] = interval;
ext_interval_idx = ++ext_interval_idx % EXT_INTERVAL_BUFFER_SIZE;
break;
}
}

19
src/uClock.h
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@ -3,7 +3,7 @@
* Project BPM clock generator for Arduino
* @brief A Library to implement BPM clock tick calls using hardware timer1 interruption. Tested on ATmega168/328, ATmega16u4/32u4 and ATmega2560.
* Derived work from mididuino MidiClock class. (c) 2008 - 2011 - Manuel Odendahl - wesen@ruinwesen.com
* @version 0.9.3
* @version 0.9.4
* @author Romulo Silva
* @date 08/21/2020
* @license MIT - (c) 2020 - Romulo Silva - contact@midilab.co
@ -35,6 +35,8 @@
#define PHASE_FACTOR 16
#define EXT_INTERVAL_BUFFER_SIZE 40
#define SECS_PER_MIN (60UL)
#define SECS_PER_HOUR (3600UL)
#define SECS_PER_DAY (SECS_PER_HOUR * 24L)
@ -47,11 +49,6 @@ enum {
STARTED
} state;
enum {
INTERNAL_CLOCK = 0,
EXTERNAL_CLOCK
} mode;
class uClockClass {
private:
@ -67,7 +64,6 @@ class uClockClass {
volatile uint16_t interval;
volatile uint16_t last_clock;
uint8_t ppqn;
uint32_t div96th_counter;
uint32_t div32th_counter;
uint32_t div16th_counter;
@ -77,13 +73,16 @@ class uClockClass {
uint16_t pll_x;
uint8_t internal_drift;
uint8_t external_drift;
uint16_t tempo;
float tempo;
uint32_t start_timer;
uint8_t mode;
uint16_t last_interval;
uint16_t sync_interval;
uint16_t ext_interval_buffer[EXT_INTERVAL_BUFFER_SIZE];
uint16_t ext_interval_idx;
public:
uint8_t INTERNAL_CLOCK = 0;
@ -122,8 +121,8 @@ class uClockClass {
void start();
void stop();
void pause();
void setTempo(uint16_t bpm);
uint16_t getTempo();
void setTempo(float bpm);
float getTempo();
void setDrift(uint8_t internal, uint8_t external = 255);
// external timming control

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