From a5153ef10b6988f2de3c6abd4facf77ac3e494c6 Mon Sep 17 00:00:00 2001
From: Quentin Bolsee <quentin.bolsee@cba.mit.edu>
Date: Tue, 26 Mar 2024 01:50:18 +0000
Subject: [PATCH] Update file ring.RP2040PIO_NO_SYNC.py

---
 py/ring.RP2040PIO_NO_SYNC.py | 39 ++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 py/ring.RP2040PIO_NO_SYNC.py

diff --git a/py/ring.RP2040PIO_NO_SYNC.py b/py/ring.RP2040PIO_NO_SYNC.py
new file mode 100644
index 0000000..6735117
--- /dev/null
+++ b/py/ring.RP2040PIO_NO_SYNC.py
@@ -0,0 +1,39 @@
+#
+# ring.RP2040PIO_NO_SYNC.py
+#    RP2040 ring oscillator with PIO + bypass synchronizer
+#    connect P1 and P2
+#
+# Quentin Bolsee 2024-03-25
+#
+# 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, mem32
+import rp2
+
+
+@rp2.asm_pio(out_init=rp2.PIO.OUT_LOW)
+def ring():
+    mov(pins, invert(pins))
+
+
+# clock speed
+# freq(133000000)
+freq(250000000)
+
+# IO pins
+pin_in = Pin(1, Pin.IN)
+pin_out = Pin(2, Pin.OUT)
+
+# bypass PIO input synchronizer on pin 1
+PIO0 = const(0x50200000)
+INPUT_SYNC_BYPASS = const(0x038)
+mem32[PIO0 + INPUT_SYNC_BYPASS] |= 1 << 1
+
+# create and launch state machine
+sm = rp2.StateMachine(0, ring, in_base=pin_in, out_base=pin_out)
+sm.active(1)
-- 
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