adding sense HAT overlay

rough overlay (refinements to come) for Sense HAT

src/en-GB/overlay/sense-hat.md

@@ -0,0 +1,41 @@
+<!--
+---
+name: "Sense HAT"
+manufacturer: Raspberry Pi Foundation
+url: https://www.raspberrypi.org/products/sense-hat/
+description: Add-on board that includes an 8×8 RGB LED matrix, 5-button joystick as well as IMU and environmental sensors 
+install:
+  'devices':
+    - 'i2c'
+    - 'spi'    
+pincount: 40
+pin:
+  3:
+    mode: i2c
+  5:
+    mode: i2c
+  16:
+    name: Joystick
+    mode: input
+  18:
+    name: Joystick
+    mode: input
+  19:
+    mode: spi
+  21:
+    mode: spi
+  22:
+    name: Joystick
+    mode: input
+  23:
+    mode: spi
+  24:
+    mode: spi
+-->
+#Sense HAT
+
+LED Matrix: LED2472G -> ATTINY88 -> SPI(8/9/10/11)
+Joystick: SKRHABE010 -> ATTINY88 -> GPIO23/24/25
+Axis/IMU: LSM9DS1 -> i2c 0x1c(1e),0x6a(6b) (INT on MCU)
+Pressure/Temp: LPS25H -> i2c 0x5c
+Humidity/Temp: HTS221 -> i2c 0x5f

src/en-GB/settings.yaml

@@ -29,3 +29,4 @@ overlays:
 - traffic-hat
 - iqaudio-pi-dac
 - piano-hat
+- sense-hat