I'll throw my hat into the ring here . . .
Since calling
while (usbMIDI.read()); in the
setup() function has been demonstrated to be ineffective at flushing the buffered clock messages, that got me to wondering if maybe something happens WRT the usbMIDI interface between the time that the
setup() function completes & the time that the
loop() function begins. So, my radical idea was to attempt to empty the buffered clock messages on the very first pass (& only the first pass) thru the
loop() function. I offer the following, which seems to effectively flush the buffered clock messages (I used the "MIDI Sync Transport" capability in MIDI-OX to continuously generate MIDI clock messages . . . hopefully with the same effect as your Reaper):
Code:
#include <USBHost_t36.h>
#include <MIDI.h>
USBHost thisUSB;
USBHub hub1(thisUSB);
MIDIDevice_BigBuffer usbhostMIDI(thisUSB);
MIDI_CREATE_DEFAULT_INSTANCE();
unsigned long currentRXtime;
unsigned long previousRXtime;
bool initial_pass_only = true;
void setup() {
// start the USBhost for MIDI inputs/devices
usbhostMIDI.begin();
// Initiate MIDI communications, listen to all channels
MIDI.begin(MIDI_CHANNEL_OMNI);
Serial.begin(57600);
delay(10000); // wait 10 secs
}
void loop() {
if (initial_pass_only)
{
// NOTE: proper credit to Paul Stoffregen for the method of flushing for a quarter second
elapsedMillis msec = 0;
while (msec < 250) {
usbMIDI.read(); // consume MIDI messages for 1/4 second
};
}
initial_pass_only = false;
if (usbMIDI.read()) {
if (usbMIDI.Clock) {
currentRXtime = micros();
Serial.print(currentRXtime - previousRXtime); Serial.print("\t"); Serial.println("F8");
previousRXtime = currentRXtime;
}
}
}
Someone with a more detailed understanding of exactly what's going on under the covers will have to explain why this approach appears to have the desired effect, as that level of understanding would be way above my pay grade !!
Mark J Culross
KD5RXT
P.S. The use of the following is leftover from my attempt at getting my USB MIDI keyboard to generate the clocks, & hopefully this is not influencing the results in any way:
Code:
USBHost thisUSB;
USBHub hub1(thisUSB);
MIDIDevice_BigBuffer usbhostMIDI(thisUSB);
MIDI_CREATE_DEFAULT_INSTANCE();
MJC
