.. _ref_nanopc_based_onboard_computer:

*****************************
NanoPC-based Onboard Computer
*****************************

Revision History
================

+----------+-------------------+-------------+---------------------------------------------------------+
| Revision | Date (DD/MM/YYYY) | Author      | Changes                                                 |
+==========+===================+=============+=========================================================+
| 1        | 18/4/2024         | Ruixiang Du | Initial release                                         |
+----------+-------------------+-------------+---------------------------------------------------------+
| 2        | 16/5/2024         | Ruixiang Du | Added information about the RS232-2 port reconfiguration|
+----------+-------------------+-------------+---------------------------------------------------------+

This onboard computer is based on NanoPC-T6. We extended the board with industrial ports for easy and reliable interfacing with commonly used sensors and robot bases. Drivers to the ports are pre-configured under Ubuntu 22.04.

.. image:: /periph_user_guide/westonrobot/figures/nanopc_sbc.jpg
    :width: 450 px

Key Specifications
==================

* **SoC: Rockchip RK3588**
* **RAM: 64-bit 8GB/16GB LPDDR4X at 2133MHz**
* **Storage: 128GB/256GB eMMC**
* **MicroSD**: support up to SDR104 mode (microSD card not included)
* **Ethernet**: 2x PCIe 2.5G Ethernet
* **USB-A**: 1x USB 3.0 Type-A
* **USB-C**: 1x Full function USB Type‑C port, support DP display up to 4Kp60, USB 3.0
* **Video**: 1x Standard HDMI input port, up to 4Kp60, 2x Standard HDMI output ports
* **Audio** 1x 3.5mm jack for stereo headphone output, 1x 2.0mm PH-2A connector for analog microphone input
* **Industrial ports**
    * 3x CAN interfaces (with transceivers)
    * 2x RS485 interfaces
    * 2x RS232 interfaces
* **Active Cooling**: 1x 5V Fan
* **Power supply**: 5.5*2.1mm DC Jack, 5V~20V, 12V is recommended.
* **Ambient Operating Temperature**: 0℃ to 70℃
* **OS**: Ubuntu 22.04 (Linux kernel 5.10)

You can find more information about the NanoPC-T6 base board (not including the extensions made by Weston Robot) from its official `wiki page <https://wiki.friendlyelec.com/wiki/index.php/NanoPC-T6>`_. 

Industrial Ports
================

.. image:: /periph_user_guide/westonrobot/figures/nanopc_industrial_ports.png
    :width: 450 px

You can follow the silk screen on the board to connect your devices to the industrial ports. 

The RS232 and RS485 ports can be access at:

* RS232-1: ``/dev/ttyS0``
* RS232-2: ``/dev/ttyS7``
* RS485-1: ``/dev/ttyS6``
* RS485-2: ``/dev/ttyS4``

.. note::
    The RS232-2 port can be configured as a TTL UART port by re-configure the jumper solder pads (JP1 and JP2). If you bridge the pad in the middle and the side marked as "TTL", the port will be configured as a TTL UART port. If you bridge the pad in the middle and the other side, the port will be configured as an RS232 port. Both TTL and RS232 UART port is accessed at ``/dev/ttyS7``.If no bridge is made, the port only provides power and no signal is transmitted. 

You need to bring up the CAN interfaces before you can access them. Here is an example to bring up the CAN0 interface (you may adjust the bitrate according to your CAN devices):

.. code-block:: bash

    $ sudo ip link set can0 up type can bitrate 500000
    $ sudo ip link set can0 txqueuelen 1000

You can also add the following configuration to ``/etc/network/interfaces`` to make the CAN interface persistent:

.. code-block:: bash

    auto can0
        iface can0 inet manual
        pre-up /sbin/ip link set can0 type can bitrate 500000
        up /sbin/ifconfig can0 up
        post-up /sbin/ip link set can0 txqueuelen 10000
        down /sbin/ifconfig can0 down

    auto can1
        iface can1 inet manual
        pre-up /sbin/ip link set can1 type can bitrate 500000
        up /sbin/ifconfig can1 up
        post-up /sbin/ip link set can1 txqueuelen 10000
        down /sbin/ifconfig can1 down

    auto can2
        iface can2 inet manual
        pre-up /sbin/ip link set can2 type can bitrate 500000
        up /sbin/ifconfig can2 up
        post-up /sbin/ip link set can2 txqueuelen 10000
        down /sbin/ifconfig can2 down

.. note::
    You may toggle the dip switches to enable the termination resistors for the CAN and RS485 interfaces. The termination resistors are disabled by default.

.. warning::
    Please note that the 5V output is limited by a resettable fuse rated at **300mA**. So please make sure the total current consumption of all devices connected to the 5V outputs does not exceed 300mA.