micropython: add micropython component

components/language/micropython/examples/rp2/pio_pinchange.py

@@ -0,0 +1,46 @@
+# Example using PIO to wait for a pin change and raise an IRQ.
+#
+# Demonstrates:
+#   - PIO wrapping
+#   - PIO wait instruction, waiting on an input pin
+#   - PIO irq instruction, in blocking mode with relative IRQ number
+#   - setting the in_base pin for a StateMachine
+#   - setting an irq handler for a StateMachine
+#   - instantiating 2x StateMachine's with the same program and different pins
+
+import time
+from machine import Pin
+import rp2
+
+
+@rp2.asm_pio()
+def wait_pin_low():
+    wrap_target()
+
+    wait(0, pin, 0)
+    irq(block, rel(0))
+    wait(1, pin, 0)
+
+    wrap()
+
+
+def handler(sm):
+    # Print a (wrapping) timestamp, and the state machine object.
+    print(time.ticks_ms(), sm)
+
+
+# Instantiate StateMachine(0) with wait_pin_low program on Pin(16).
+pin16 = Pin(16, Pin.IN, Pin.PULL_UP)
+sm0 = rp2.StateMachine(0, wait_pin_low, in_base=pin16)
+sm0.irq(handler)
+
+# Instantiate StateMachine(1) with wait_pin_low program on Pin(17).
+pin17 = Pin(17, Pin.IN, Pin.PULL_UP)
+sm1 = rp2.StateMachine(1, wait_pin_low, in_base=pin17)
+sm1.irq(handler)
+
+# Start the StateMachine's running.
+sm0.active(1)
+sm1.active(1)
+
+# Now, when Pin(16) or Pin(17) is pulled low a message will be printed to the REPL.