Update file ring.RP2040PIO_NO_SYNC.py

py/ring.RP2040PIO_NO_SYNC.py

+#
+# 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)