Refactor processing units chapter

Author: fjp

docs/git-setup.md docs/processing_units/git-setup.mddocs/git-setup.md renamed to docs/processing_units/git-setup.md

@@ -0,0 +1,18 @@
+# Processing Units
+
+Our robot consists of components which are connected as shown in the block diagram below:
+
+![Block Diagram Remo]({{ asset_dir }}/processing_units/block-diagram-remo.svg)
+
+The Teensy 3.2 microcontroller board is connected to the encoder and optional IMU
+sensor as well as the motor driver actuator. It communicates to the Raspberry Pi 4 B via
+USB over the `rosserial` protocol. The motor driver and the optional IMU exchange
+data over I2C with the microcontroller. The RPLIDAR has a serial-to-USB converter and
+is therefore connected to one of the USB ports of the SBC. The motor encoder sensors
+are interfaced through the GPIO pins of the microcontroller. The following shows the
+connection diagram of the components:
+
+
+[![Remo Fritzing]][Remo Fritzing]
+
+  [Remo Fritzing]: /fritzing/remo_architecture.svg

docs/hardware-interfaces.md …/processing_units/hardware-interfaces.mddocs/hardware-interfaces.md renamed to docs/processing_units/hardware-interfaces.md docs/hardware-interfaces.md renamed to docs/processing_units/hardware-interfaces.md

@@ -90,14 +90,15 @@ nav:
     - Assembly: hardware_setup/assembly.md
     - Install: hardware_setup/install.md
   - Processing Units:
+    - processing_units/index.md
     - Single Board Computer:
-      - Raspberry Pi Setup: rpi-setup.md
-      - Jetson Nano Setup: jetson-nano-setup.md
-      - Git Setup: git-setup.md
-      - ROS Setup: ros-setup.md
-    - Microcontroller: packages/diffbot_base/scripts/teensy-mcu.md
-    - Hardware Interfaces: hardware-interfaces.md
-    - ROS Network Setup: ros-network-setup.md
+      - Raspberry Pi Setup: processing_units/rpi-setup.md
+      - Jetson Nano Setup: processing_units/jetson-nano-setup.md
+      - Git Setup: processing_units/git-setup.md
+      - ROS Setup: processing_units/ros-setup.md
+    - Microcontroller: processing_units/teensy-mcu.md
+    - Hardware Interfaces: processing_units/hardware-interfaces.md
+    - ROS Network Setup: processing_units/ros-network-setup.md
   - ROS Software Packages:
     - packages/index.md
     - Packages: packages.md