Fix bug in EPD wait method.

drivers/epaper/epaper2in7_fb.py

@@ -131,6 +131,7 @@ class EPD(framebuf.FrameBuffer):
         print('wait_until_ready {}ms {:5.1f}mins'.format(dt, dt/60_000))
 
     async def wait(self):
+        await asyncio.sleep_ms(0)  # Ensure tasks run that might make it unready
         while not self.ready():
             await asyncio.sleep_ms(100)
 

drivers/epaper/epd29.py

@@ -109,17 +109,14 @@ class EPD(framebuf.FrameBuffer):
         print('Init Done.')
 
     # For use in synchronous code: blocking wait on ready state.
-    # TODO remove debug code from Waveshare fiasco.
     def wait_until_ready(self):
         sleep_ms(50)
-        t = ticks_ms()
         while not self.ready():  
             sleep_ms(100)
-        dt = ticks_diff(ticks_ms(), t)
-        print('wait_until_ready {}ms {:5.1f}mins'.format(dt, dt/60_000))
 
     # Asynchronous wait on ready state. Pause (4.9s) for physical refresh.
     async def wait(self):
+        await asyncio.sleep_ms(0)  # Ensure tasks run that might make it unready
         while not self.ready():
             await asyncio.sleep_ms(100)
 

gui/demos/epd29_async.py

@@ -31,7 +31,7 @@ def xorshift64star(modulo, seed = 0xf9ac6ba4):
         return (x * 0x2545F4914F6CDD1D) % modulo
     return func
 
-async def compass(evt):  # TODO why does this not get drawn on 1st pass?
+async def compass(evt):
     wri = Writer(ssd, arial10, verbose=False)
     wri.set_clip(False, False, False)
     v1 = 0 + 0.9j
@@ -42,7 +42,6 @@ async def compass(evt):  # TODO why does this not get drawn on 1st pass?
     while True:
         ptr.value(v1)
         v1 *= v2
-#        await asyncio.sleep_ms(100)
         await evt.wait()