Question: compat_mode for i2c or using lib with threads? about rplcd

[dbrgn]

If you use two parallel threads, then there's always a chance for race conditions between the two. A compat mode won't help here. RPCLD is not thread safe, a multi-threaded application needs to synchronize access to the LCD.

My suggestion would be to have a single thread that writes to the display. Other threads could then send "write requests" through something like a channel or synchronized queue, which the writing thread processes and writes to the display.

[OllisGit]

Thanks for the fast response and the advice.

I think I found a solution for me. Instead of a single thread as you suggested, I use a threading.lock.

Now my test program works fine, even with 10 threads!

lock = threading.Lock()

def call_plugins(storage, filename, progress):
    lock.acquire()
    mylcd.clear()
    mylcd.write_string('Printing...')
    mylcd.cursor_pos = (1 ,0)
    mylcd.write_string('Layer: ' + str(storage))
    lock.release()

[dbrgn]

Yep, that works as well for synchronization 🙂