py implementation

README.md

-# rp2040-ring-pio
+# Ring oscillator with RP2040 PIO, MicroPython implementation
 
 This is a demonstration of the RP2040's PIO system, which let you run several state machines independently of the CPU. There's exactly 0 overhead and the state machines run a custom assembly language with simplified instructions.
 
 In this example implementation of a [ring oscillator](https://pub.pages.cba.mit.edu/ring/), pin 1 is configured as a PIO input, and pin 2 as an output. Reading, inverting and writing is as simple as:
 
 ```
-.program ring
-    mov pins, !pins
-.wrap
+mov pins, !pins
 ```
 
 Where `pins` is a meta keyword, with a different meaning in the first and second operand (output VS input, respectively).
@@ -19,23 +17,10 @@ Where `pins` is a meta keyword, with a different meaning in the first and second
 | 133 MHz  | 16.667 MHz |
 | 250 MHz  | 25 MHz     |
 
-## Binaries
+## C implementation
 
-You can find compiled binaries in [build/](./build/). Simply drang and drop the `.uf2` file on your raspberry pi pico's storage space after putting it in reset mode (boot button + power cycle).
+The original C implementation can be found [here](./c).
 
-## Build
+## MicroPython implementation
 
-Navigate to `build/` and generate the project using cmake:
-
-```
-cd build/
-cmake ..
-```
-
-This should create a Makefile, and you can simply build the project every time you update the code by running:
-
-```
-make
-```
-
-The output is `bin`, `elf`, `hex` and `uf2` files in `build/`.
+A MicroPython version with the same performance can be found [here](./py).

c/README.md

+# Ring oscillator with RP2040 PIO, C implementation
+
+This is a demonstration of the RP2040's PIO system, which let you run several state machines independently of the CPU. There's exactly 0 overhead and the state machines run a custom assembly language with simplified instructions.
+
+## Binaries
+
+You can find compiled binaries in [build/](./build/). Simply drang and drop the `.uf2` file on your raspberry pi pico's storage space after putting it in reset mode (boot button + power cycle).
+
+## Build
+
+Navigate to `build/` and generate the project using cmake:
+
+```
+cd build/
+cmake ..
+```
+
+This should create a Makefile, and you can simply build the project every time you update the code by running:
+
+```
+make
+```
+
+The output is `bin`, `elf`, `hex` and `uf2` files in `build/`.

py/README.md

+# Ring oscillator with RP2040 PIO, C implementation
+
+Here is a MicroPython implementation of using the RP2040's PIO system for a [ring oscillator](https://pub.pages.cba.mit.edu/ring/). The PIO asm is a one liner:
+
+```
+mov pins, !pins
+```
+
+The rest of the code simply sets up the state machine and optionally overclocks the RP2040 to 250MHz.
+
+## Installing MicroPython
+
+You can install MicroPython from [the official website](https://micropython.org/download/), and a good setup guide can be found [here](https://wiki.seeedstudio.com/XIAO-RP2040-with-MicroPython/).
+
+## Code
+
+The code can be found [here](./ring.RP2040PIO.py), but it's short enough to paste here:
+
+```py
+#
+# ring.RP2040PIO.py
+#    RP2040 ring oscillator with PIO
+#    connect P1 and P2
+#
+# Quentin Bolsee 12/27/22
+#
+# This work may be reproduced, modified, distributed,
+# performed, and displayed for any purpose, but must
+# acknowledge this project. Copyright is retained and
+# must be preserved. The work is provided as is; no
+# warranty is provided, and users accept all liability.
+#
+
+from machine import Pin, freq
+import rp2
+
+
+@rp2.asm_pio(out_init=rp2.PIO.OUT_LOW)
+def ring():
+    mov(pins, invert(pins))
+
+
+# clock speed
+# freq(133000000)
+freq(250000000)
+pin_in = Pin(1, Pin.IN)
+pin_out = Pin(2, Pin.OUT)
+sm = rp2.StateMachine(0, ring, in_base=pin_in, out_base=pin_out)
+sm.active(1)
+```

py/ring.RP2040PIO.py

+#
+# ring.RP2040PIO.py
+#    RP2040 ring oscillator with PIO
+#    connect P1 and P2
+#
+# Quentin Bolsee 12/27/22
+#
+# This work may be reproduced, modified, distributed,
+# performed, and displayed for any purpose, but must
+# acknowledge this project. Copyright is retained and
+# must be preserved. The work is provided as is; no
+# warranty is provided, and users accept all liability.
+#
+
+from machine import Pin, freq
+import rp2
+
+
+@rp2.asm_pio(out_init=rp2.PIO.OUT_LOW)
+def ring():
+    mov(pins, invert(pins))
+
+
+# clock speed
+# freq(133000000)
+freq(250000000)
+pin_in = Pin(1, Pin.IN)
+pin_out = Pin(2, Pin.OUT)
+sm = rp2.StateMachine(0, ring, in_base=pin_in, out_base=pin_out)
+sm.active(1)