Added Propeller HAT

src/en/overlay/propeller-hat.md

@@ -0,0 +1,40 @@
+<!--
+---
+class: board
+type: other
+name: Propeller HAT
+featured: true
+image: 'propeller-hat.png'
+manufacturer: Pimoroni
+description: The 8-core Propeller Microcontroller in HAT form-factor
+url: http://shop.pimoroni.com/products/propeller-hat
+github: https://github.com/pimoroni/piano-hat
+buy: https://shop.pimoroni.com/products/propeller-hat
+formfactor: 'HAT'
+pincount: 40
+eeprom: yes
+power:
+  '2':
+ground:
+  '6':
+pin:
+  '8':
+    name: TXD / Transmit
+    direction: output
+    active: high
+  '10':
+    name: RXD / Receive
+    direction: input
+    active: high
+  '11':
+    name: Reset
+    active: low
+  '29':
+    name: EEPROM WP
+    active: low
+-->
+#Propeller HAT
+
+Propeller HAT brings the 8-core Parallax Propeller microcontroller to HAT form-factor. Program and talk to it over Serial using Propeller IDE and you'll have a powerful, realtime co-processor for your Pi.
+
+It's like a little software programming logic device. Great for realtime IO, servo control and even convincingly synthesizing a SID chip.