Is it possible to initialize the beatsin8() function to a fixed starting point?

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1

Is it possible to initialize the beatsin8() function to a fixed starting point? Right now, when I call the function, it returns wherever it’s currently at in the wave form. I would like it to always start from 0 whenever I call it.

2

Yes. On the 3.1 branch, you can specify a base timestamp.

uint8_t beatsin8(
accum88 beats_per_minute,
uint8_t lowest=0,
uint8_t highest=255,
uint32_t timebase=0,
uint8_t phase_offset=0)

So when you want to ‘zero’ out the beat, do this:
uint32_t zerotime = millis();

And then when you call beatsin8, pass in ‘zerotime’ as the fourth argument:
uint8_t wave = beatsin8( 120, 0, 255, zerotime);

That should do it. Let me know if it doesn’t work! (Or if it does, too!)

3

Oooh nice, that’s great to know.

4

That makes this function much more awesome.

5

Worked like a charm! Here is the code I used to reset the BPM generator upon receiving a new tempo command :

if (new_BPM)
{
zerotime = millis();
tempo = beatsin8( data2, 0, NUM_ROWS, zerotime );
new_BPM = false;
}
else
{
tempo = beatsin8( data2, 0, NUM_ROWS );
}

6

I think you might mean this:

if (new_BPM) {
zerotime = millis();
new_BPM = false;
}

tempo = beatsin8( data2, 0, NUM_ROWS, zerotime );

Basically, you have to always tell beatsin8 what you want the base time to be; it doesn’t have any internal state.

7

@Mark_Kriegsman OK, that makes sense and operates as expected, thank you.