solutions for non-blocking rtttl ringtones?

[dukeduck]

Hi,

I'm trying to implement upy-rtttl (https://github.com/dhylands/upy-rtttl) in my project in a non-blocking way.

My current solution is to use '_thread'.

The orignial example of upy-rtttl is shown as below: (https://github.com/dhylands/upy-rtttl/b ... yb_test.py)
```
def play_song(search):
play(RTTTL(songs.find(search)))
```

My implementation with _thread is:
```
def play_song(self, search):
_thread.start_new_thread(self.play, (RTTTL(songs.find(search)),))
```

It worked when run alone (without other major tasks), however when running with other tasks, the sound showed obvious delay (jagged), and very often I got: RuntimeError: maximum recursion depth exceeded

The trackback points to the "parse_defaults" method in class RTTTL (https://github.com/dhylands/upy-rtttl/b ... r/rtttl.py)

My questions:
1. Is there a better way to do it in a non-blocking way?
2. What could be the possible cause of the RuntimeError: maximum recursion depth exceeded? The stack size of the thread was too little?

Thanks in advance!
Kaiyuan

[fstengel]

2. What could be the possible cause of the RuntimeError: maximum recursion depth exceeded? The stack size of the thread was too little?

That is indeed a possibility. This error is thrown when the stack overflows, and that usually happens when there is a runaway recursion. According to the current source, the default stack size is 5kB.

[jimmo]

If you want to increase the thread stack size, you can set

Code: Select all

_thread.stack_size = 8192

Note the default on ESP32 is 5kiB, the minimum is 4kiB.


The probably better solution to your problem is to use (u)asyncio, but that will likely require a significant re-writing of the rtttl library and your application. (But it might be worth it!) Note that https://github.com/micropython/micropython/pull/5332 is about to be merged and may be of interest.

[dhylands]

I'm not sure that any changes need to be made to upy-rtttl to support asyncio. The library was designed as a generator which returns a tuples. Each tuple contains the note to play and how long to play it for. Each time you call the generator it returns the next tuple.

upy-rtttl doesn't have any internal delays or other blocking operations. That's all left to the calling code.

upy-rtttl also doesn't use any recursion.

[dukeduck]

I'm not sure that any changes need to be made to upy-rtttl to support asyncio. The library was designed as a generator which returns a tuples. Each tuple contains the note to play and how long to play it for. Each time you call the generator it returns the next tuple.

upy-rtttl doesn't have any internal delays or other blocking operations. That's all left to the calling code.

upy-rtttl also doesn't use any recursion.

Thanks for creating and sharing the upy-rtttl library @dhylands.

I guess it may not be appropriate to call it blocking - what I tried to say was that when using rtttl with another task, say a timer, the timer can still work properly when the loop is generating tones.

Thanks for the advise @jimmo @fstengel. I will try increasing the stack size to see if it will solve the issue.

Thanks again.
Kaiyuan