Documentation for Ring-testing (#51)

docs/examples/ring-testing.md

@@ -0,0 +1,31 @@
+# Ring Testing example
+
+!!! info "Schematic"
+    === "Pocket Beagle"
+        ![](images/ring_testing.png)
+
+
+
+## Code
+
+```python
+while : true
+{
+if: digital_read(P1_33)
+{
+    digital_write(P1_36, true);
+}
+else
+{
+    digital_write(P1_36, false);
+}
+}
+```
+
+* This is the code for ring-testing with simpPRU on PocketBeagle,the pinout given works well for this testing.
+
+## Explaination
+The above code is in simpPRU which is equivalent to [PRU C](https://github.com/beagleboard/cloud9-examples/blob/v2020.01/PocketBeagle/pru/ring.pru0.c).
+
+This code runs a never ending loop, since it is `while : true`. 
+Inside `while` it reads header pin P1_33, it checks if header pin P1_33 is HIGH or LOW.If header pin P1_33 is HIGH, header pin P1_36 is set to LOW, and if header pin P1_33 is LOW, header pin P1_36 is set to HIGH.