Add some examples, improve the assembler

adafruit_pioasm.py

@@ -31,7 +31,7 @@
 
 def assemble(text_program):
     """Converts pioasm text to encoded instruction bytes"""
-    # pylint: disable=too-many-branches,too-many-statements
+    # pylint: disable=too-many-branches,too-many-statements,too-many-locals
     assembled = []
     program_name = None
     labels = {}
@@ -55,7 +55,10 @@ def assemble(text_program):
         elif line.startswith(".side_set"):
             sideset_count = int(line.split()[1])
         elif line.endswith(":"):
-            labels[line[:-1]] = len(instructions)
+            label = line[:-1]
+            if label in labels:
+                raise SyntaxError(f"Duplicate label {repr(label)}")
+            labels[label] = len(instructions)
         elif line:
             # Only add as an instruction if the line isn't empty
             instructions.append(line)
@@ -85,10 +88,13 @@ def assemble(text_program):
         elif instruction[0] == "jmp":
             #                instr delay cnd addr
             assembled.append(0b000_00000_000_00000)
-            if instruction[-1] in labels:
-                assembled[-1] |= labels[instruction[-1]]
+            target = instruction[-1]
+            if target[:1] in "0123456789":
+                assembled[-1] |= int(target)
+            elif instruction[-1] in labels:
+                assembled[-1] |= labels[target]
             else:
-                assembled[-1] |= int(instruction[-1])
+                raise SyntaxError(f"Invalid jmp target {repr(target)}")
 
             if len(instruction) > 2:
                 assembled[-1] |= CONDITIONS.index(instruction[1]) << 5

examples/getting-started/README.md

@@ -0,0 +1,7 @@
+<!--
+SPDX-FileCopyrightText: 2020 Jeff Epler, written for Adafruit Industries
+
+SPDX-License-Identifier: MIT
+-->
+
+These examples are adapted from [Getting started with MicroPython on the Raspberry Pi Pico](https://www.adafruit.com/product/4898).  You can also get an [electonic copy](https://hackspace.raspberrypi.org/books/micropython-pico/).  PIO is covered in Appendix C.

examples/getting-started/led_brightness.py

@@ -0,0 +1,49 @@
+# SPDX-FileCopyrightText: 2021 Jeff Epler, written for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+#
+# Adapted from the an example in Appendix C of RPi_PiPico_Digital_v10.pdf
+
+import time
+import board
+import rp2pio
+import adafruit_pioasm
+
+led_quarter_brightness = adafruit_pioasm.assemble(
+    """
+    set pins, 0 [2]
+    set pins, 1
+"""
+)
+
+led_half_brightness = adafruit_pioasm.assemble(
+    """
+    set pins, 0
+    set pins, 1
+"""
+)
+
+led_full_brightness = adafruit_pioasm.assemble(
+    """
+    set pins, 1
+"""
+)
+
+while True:
+    sm = rp2pio.StateMachine(
+        led_quarter_brightness, frequency=10000, first_set_pin=board.LED
+    )
+    time.sleep(1)
+    sm.deinit()
+
+    sm = rp2pio.StateMachine(
+        led_half_brightness, frequency=10000, first_set_pin=board.LED
+    )
+    time.sleep(1)
+    sm.deinit()
+
+    sm = rp2pio.StateMachine(
+        led_full_brightness, frequency=10000, first_set_pin=board.LED
+    )
+    time.sleep(1)
+    sm.deinit()

examples/pico-examples/README.md

@@ -0,0 +1,7 @@
+<!--
+SPDX-FileCopyrightText: 2020 Jeff Epler, written for Adafruit Industries
+
+SPDX-License-Identifier: MIT
+-->
+
+These examples are adapted from the pio folder of the [Raspberry Pi Pico SDK Examples](https://github.com/raspberrypi/pico-examples).

examples/pico-examples/hello.py

@@ -0,0 +1,37 @@
+# SPDX-FileCopyrightText: 2021 Jeff Epler, written for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+#
+# Adapted from the example https://github.com/raspberrypi/pico-examples/tree/master/pio/hello_pio
+
+import time
+import board
+import rp2pio
+import adafruit_pioasm
+
+hello = """
+.program hello
+loop:
+    pull
+    out pins, 1
+; This program uses a 'jmp' at the end to follow the example.  However,
+; in a many cases (including this one!) there is no jmp needed at the end
+; and the default "wrap" behavior will automatically return to the "pull"
+; instruction at the beginning.
+    jmp loop
+"""
+
+assembled = adafruit_pioasm.assemble(hello)
+
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+    first_out_pin=board.LED,
+)
+print("real frequency", sm.frequency)
+
+while True:
+    sm.write(bytes((1,)))
+    time.sleep(0.5)
+    sm.write(bytes((0,)))
+    time.sleep(0.5)