diff --git a/DRIVERS.md b/DRIVERS.md
index 205164b..8abec9c 100644
--- a/DRIVERS.md
+++ b/DRIVERS.md
@@ -1039,8 +1039,8 @@ see below.
  * `rst` An initialised output pin. Initial value should be 1.
  * `busy` An initialised input pin.
  * `landscape=True` By default the long axis is horizontal.
- * `asyn=False` Setting this `True` invokes an asynchronous mode. See
- [EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
+
+The `asyn` arg has been removed: the driver now detects asynchronous use.
 
 ### 5.1.2 Public methods
 
@@ -1058,9 +1058,9 @@ All methods are synchronous.
 
 ### 5.1.3 Events
 
-These provide synchronisation in asynchronous applications where `asyn=True`.
-They are only needed in more advanced asynchronous applications and their use
-is discussed in [EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
+These provide synchronisation in asynchronous applications. They are only
+needed in more advanced asynchronous applications and their use is discussed in
+[EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
  * `updated` Set when framebuf has been copied to device. It is now safe to
  modify widgets without risk of display corruption.
  * `complete` Set when display update is complete. It is now safe to call
@@ -1227,8 +1227,8 @@ Pins 26-40 unused and omitted.
  * `rst` An initialised output pin. Initial value should be 1.
  * `busy` An initialised input pin.
  * `landscape=False` By default the long axis is vertical.
- * `asyn=False` Setting this `True` invokes an asynchronous mode. See
- [EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
+
+The `asyn` arg has been removed: the driver now detects asynchronous use.
 
 ### 5.2.2 EPD public methods
 
@@ -1246,9 +1246,9 @@ All methods are synchronous.
 
 ### 5.2.3 Events
 
-These provide synchronisation in asynchronous applications where `asyn=True`.
-They are only needed in more advanced asynchronous applications and their use
-is discussed in [EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
+These provide synchronisation in asynchronous applications. They are only
+needed in more advanced asynchronous applications and their use is discussed in
+[EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
  * `updated` Set when framebuf has been copied to device. It is now safe to
  modify widgets without risk of display corruption.
  * `complete` Set when display update is complete. It is now safe to call
@@ -1280,8 +1280,7 @@ import gc
 from drivers.epaper.pico_epaper_42 import EPD as SSD
 
 gc.collect()  # Precaution before instantiating framebuf.
-ssd = SSD()  # Create a display instance. For normal applications.
-# ssd = SSD(asyn=True)  # Alternative for asynchronous applications.
+ssd = SSD()  # Create a display instance based on a Pico in socket.
 ```
 ### 5.3.1 Constructor args
 
@@ -1293,8 +1292,8 @@ following constructor args:
  * `dc=None` A `Pin` instance defined as `Pin.OUT`.
  * `rst=None` A `Pin` instance defined as `Pin.OUT`.
  * `busy=None` A `Pin` instance defined as `Pin.IN, Pin.PULL_UP`.
- * `asyn=False` Set `True` for asynchronous applications. Leave `False` for
- microgui where the arg has no effect.
+
+The `asyn` arg has been removed: the driver now detects asynchronous use.
 
 ### 5.3.2 Public methods
 
@@ -1321,9 +1320,9 @@ ghosting.
 
 ### 5.3.3 Events
 
-These provide synchronisation in asynchronous applications where `asyn=True`.
-They are only needed in more advanced asynchronous applications and their use
-is discussed in [EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
+These provide synchronisation in asynchronous applications. They are only
+needed in more advanced asynchronous applications and their use is discussed in
+[EPD Asynchronous support](./DRIVERS.md#6-epd-asynchronous-support).
  * `updated` Set when framebuf has been copied to device. It is now safe to
  modify widgets without risk of display corruption.
  * `complete` Set when display update is complete. It is now safe to call
@@ -1349,8 +1348,6 @@ before issuing another refresh.
 The following applies to nano-gui. Under micro-gui the update mechanism is
 a background task. Use with micro-gui is covered
 [here](https://github.com/peterhinch/micropython-micro-gui/blob/main/README.md#10-epaper-displays).
-Further, the comments address the case where the driver is instantiated with
-`asyn=True`.
 
 When synchronous code issues
 ```python
@@ -1364,15 +1361,14 @@ refresh is complete. If `demo_mode` is set, device drivers block for an
 additional 2 seconds to enable demos written for normal displays to work (the
 2 second pause allows the result of each refresh to be seen).
 
-This long blocking period is not ideal in asynchronous code, and the process is
-modified if, in `color_setup.py`, an `EPD` is instantiated with `asyn=True`. In
-this case `refresh` calls the `show` method as before, but `show` creates a
-task `._as_show` and returns immediately. The task yields to the scheduler as
-necessary to ensure that blocking is limited to around 30ms. If screen updates
-take place at a low rate the only precaution necessary is to ensure that
-sufficient time elapses between calls to `ssd.refresh()` for the update to
-complete. For example the following code fragment illustrates an application
-which performs a full EPD refresh once per minute:
+This long blocking period is not ideal in asynchronous code. If `refresh` is
+called from a task, `refresh` calls the `show` method as before, but `show`
+creates a task `._as_show` and returns immediately. The task yields to the
+scheduler as necessary to ensure that blocking is limited to around 30ms. If
+screen updates take place at a low rate the only precaution necessary is to
+ensure that sufficient time elapses between calls to `ssd.refresh()` for the
+update to complete. For example the following code fragment illustrates an
+application which performs a full EPD refresh once per minute:
 
 ```python
 async def run():
@@ -1382,7 +1378,7 @@ async def run():
         ssd.refresh()  # Launches background refresh
         await asyncio.sleep(60)
 ```
-With `asyn=True` other running tasks experience latency measured in tens of ms.
+Other running tasks experience latency measured in tens of ms.
 
 Finer control is available using the two public bound `Event` instances. This
 fragment assumes an application with a single task performing refreshes. The
diff --git a/drivers/epaper/epaper2in7_fb.py b/drivers/epaper/epaper2in7_fb.py
index 8da044d..3d44841 100644
--- a/drivers/epaper/epaper2in7_fb.py
+++ b/drivers/epaper/epaper2in7_fb.py
@@ -3,7 +3,7 @@
 # EPD is subclassed from framebuf.FrameBuffer for use with Writer class and nanogui.
 # Optimisations to reduce allocations and RAM use.
 
-# Copyright (c) Peter Hinch 2020
+# Copyright (c) Peter Hinch 2020-2023
 # Released under the MIT license see LICENSE
 
 # Based on the following sources:
@@ -16,6 +16,13 @@ import framebuf
 import uasyncio as asyncio
 from time import sleep_ms, ticks_ms, ticks_us, ticks_diff
 
+def asyncio_running():
+    try:
+        _ = asyncio.current_task()
+    except:
+        return False
+    return True
+
 class EPD(framebuf.FrameBuffer):
     # A monochrome approach should be used for coding this. The rgb method ensures
     # nothing breaks if users specify colors.
@@ -23,6 +30,7 @@ class EPD(framebuf.FrameBuffer):
     def rgb(r, g, b):
         return int((r > 127) or (g > 127) or (b > 127))
 
+    # Discard asyn: autodetect
     def __init__(self, spi, cs, dc, rst, busy, landscape=False, asyn=False):
         self._spi = spi
         self._cs = cs  # Pins
@@ -30,7 +38,6 @@ class EPD(framebuf.FrameBuffer):
         self._rst = rst
         self._busy = busy
         self._lsc = landscape
-        self._asyn = asyn
         self._as_busy = False  # Set immediately on start of task. Cleared when busy pin is logically false (physically 1).
         self.updated = asyncio.Event()
         self.complete = asyncio.Event()
@@ -198,7 +205,7 @@ class EPD(framebuf.FrameBuffer):
 
     # draw the current frame memory. Blocking time ~180ms
     def show(self, buf1=bytearray(1)):
-        if self._asyn:
+        if asyncio_running():
             if self._as_busy:
                 raise RuntimeError('Cannot refresh: display is busy.')
             self._as_busy = True
diff --git a/drivers/epaper/epd29.py b/drivers/epaper/epd29.py
index 9f416ee..9469302 100644
--- a/drivers/epaper/epd29.py
+++ b/drivers/epaper/epd29.py
@@ -4,7 +4,7 @@
 
 # EPD is subclassed from framebuf.FrameBuffer for use with Writer class and nanogui.
 
-# Copyright (c) Peter Hinch 2020
+# Copyright (c) Peter Hinch 2020-2023
 # Released under the MIT license see LICENSE
 
 # Based on the following sources:
@@ -22,7 +22,14 @@ import uasyncio as asyncio
 from micropython import const
 from time import sleep_ms, sleep_us, ticks_ms, ticks_us, ticks_diff
 
-_MAX_BLOCK = const(20)  # Maximum blocking time (ms) for asynchronous show.
+_def asyncio_running():
+    try:
+        _ = asyncio.current_task()
+    except:
+        return False
+    return True
+
+MAX_BLOCK = const(20)  # Maximum blocking time (ms) for asynchronous show.
 
 class EPD(framebuf.FrameBuffer):
     # A monochrome approach should be used for coding this. The rgb method ensures
@@ -31,6 +38,7 @@ class EPD(framebuf.FrameBuffer):
     def rgb(r, g, b):
         return int((r > 127) or (g > 127) or (b > 127))
 
+    # Discard asyn: autodetect
     def __init__(self, spi, cs, dc, rst, busy, landscape=True, asyn=False):
         self._spi = spi
         self._cs = cs  # Pins
@@ -38,7 +46,6 @@ class EPD(framebuf.FrameBuffer):
         self._rst = rst  # Active low.
         self._busy = busy  # Active low on IL0373
         self._lsc = landscape
-        self._asyn = asyn
         # ._as_busy is set immediately on start of task. Cleared
         # when busy pin is logically false (physically 1).
         self._as_busy = False
@@ -165,7 +172,7 @@ class EPD(framebuf.FrameBuffer):
 
     # draw the current frame memory.
     def show(self, buf1=bytearray(1)):
-        if self._asyn:
+        if asyncio_running():
             if self._as_busy:
                 raise RuntimeError('Cannot refresh: display is busy.')
             self._as_busy = True  # Immediate busy flag. Pin goes low much later.
diff --git a/drivers/epaper/pico_epaper_42.py b/drivers/epaper/pico_epaper_42.py
index dc67895..4ca8521 100644
--- a/drivers/epaper/pico_epaper_42.py
+++ b/drivers/epaper/pico_epaper_42.py
@@ -45,6 +45,13 @@ import time
 import uasyncio as asyncio
 from drivers.boolpalette import BoolPalette
 
+def asyncio_running():
+    try:
+        _ = asyncio.current_task()
+    except:
+        return False
+    return True
+
 # Display resolution
 _EPD_WIDTH = const(400)
 _BWIDTH = _EPD_WIDTH // 8
@@ -111,6 +118,7 @@ class EPD(framebuf.FrameBuffer):
     def rgb(r, g, b):
         return int((r > 127) or (g > 127) or (b > 127))
 
+    # Discard asyn: autodetect
     def __init__(self, spi=None, cs=None, dc=None, rst=None, busy=None, asyn=False):
         self.reset_pin = Pin(RST_PIN, Pin.OUT) if rst is None else rst
         self.busy_pin = Pin(BUSY_PIN, Pin.IN, Pin.PULL_UP) if busy is None else busy
@@ -118,7 +126,6 @@ class EPD(framebuf.FrameBuffer):
         self.dc_pin = Pin(DC_PIN, Pin.OUT) if dc is None else dc
         self.spi = SPI(1, sck = Pin(10), mosi = Pin(11), miso = Pin(28)) if spi is None else spi
         self.spi.init(baudrate = 4_000_000)
-        self._asyn = asyn
         self._busy = False  # Set immediately on .show(). Cleared when busy pin is logically false (physically 1).
         self.updated = asyncio.Event()
         self.complete = asyncio.Event()
@@ -284,7 +291,9 @@ class EPD(framebuf.FrameBuffer):
         self._busy = False
         self.complete.set()
 
-    async def do_refresh(self, split):  # For micro-gui
+    # Specific method for micro-gui. Unsuitable EPD's lack this method. Micro-gui
+    # does not test for asyncio as this is guaranteed to be up.
+    async def do_refresh(self, split):
         assert (not self._busy), "Refresh while busy"
         await self._as_show()  # split=5
 
@@ -292,7 +301,7 @@ class EPD(framebuf.FrameBuffer):
         if self._busy:
             raise RuntimeError('Cannot refresh: display is busy.')
         self._busy = True  # Immediate busy flag. Pin goes low much later.
-        if self._asyn:
+        if asyncio_running():
             self.updated.clear()
             self.complete.clear()
             asyncio.create_task(self._as_show())
diff --git a/setup_examples/epd29_pyb_async.py b/setup_examples/epd29_pyb_async.py
index 4e1c4f6..b3283d1 100644
--- a/setup_examples/epd29_pyb_async.py
+++ b/setup_examples/epd29_pyb_async.py
@@ -38,4 +38,4 @@ pbusy = machine.Pin('Y4', machine.Pin.IN)
 # Datasheet P35 indicates up to 10MHz.
 spi = machine.SPI(2, baudrate=5_000_000)
 gc.collect()  # Precaution before instantiating framebuf
-ssd = SSD(spi, pcs, pdc, prst, pbusy, asyn=True)  # Create a display instance
+ssd = SSD(spi, pcs, pdc, prst, pbusy)  # Create a display instance
diff --git a/setup_examples/epd_waveshare_42_pico.py b/setup_examples/epd_waveshare_42_pico.py
index d365fa8..79b8f78 100644
--- a/setup_examples/epd_waveshare_42_pico.py
+++ b/setup_examples/epd_waveshare_42_pico.py
@@ -13,6 +13,6 @@ import gc
 from drivers.epaper.pico_epaper_42 import EPD as SSD
 
 gc.collect()  # Precaution before instantiating framebuf
-# Set asyn True to run asynchronous code such as epd_async.py
-# Set False for normal synchronous code e.g. other demos.
-ssd = SSD(asyn=True)  # Create a display instance
+ssd = SSD()  # Create a display instance
+# Set this to run demos written for arbitrary displays:
+# ssd.demo_mode = True
diff --git a/setup_examples/waveshare_pyb.py b/setup_examples/waveshare_pyb.py
index b94a6ca..fb8f625 100644
--- a/setup_examples/waveshare_pyb.py
+++ b/setup_examples/waveshare_pyb.py
@@ -32,5 +32,5 @@ prst = machine.Pin('Y3', machine.Pin.OUT_PP, value=1)
 pbusy = machine.Pin('Y4', machine.Pin.IN)
 spi = machine.SPI(2, baudrate=4_000_000)  # From https://github.com/mcauser/micropython-waveshare-epaper/blob/master/examples/2in9-hello-world/test.py
 gc.collect()  # Precaution before instantiating framebuf
-ssd = SSD(spi, pcs, pdc, prst, pbusy, landscape=False, asyn=True)  # Create a display instance
+ssd = SSD(spi, pcs, pdc, prst, pbusy, landscape=False)  # Create a display instance
 #ssd.demo_mode = True