.. _ardep_board_can_and_lin:
   

CAN and LIN
###########

.. contents::
   :local:
   :depth: 2

CAN and LIN share a single DB-9 connector in accordance with the Pinout proposed by Vector. 


..  figure:: can_and_lin_vectors.png
    :width: 600px

    Source: `Vector Website <https://www.vector.com/int/en/products/products-a-z/hardware/network-interfaces/cables/can-cables/#c134923>`_

On the ARDEP mainboard, the pinout is configured as shown below.
CAN Channel B is permanently connected to the DB-9 connector.
CAN Channel A and LIN are permanently connected to the spring terminal block.
Using SW1, the user can choose to connect CAN-A or LIN to the DB-9 connector. 

..  figure:: can_and_lin_db9_pinout.png
    :width: 600px

    DB-9 Pinout

..  figure:: can_and_lin_spring_terminal_pinout.png
    :width: 600px

    Spring terminal pinout

CAN
===

The ARDEP Mainboard comes with two CAN-FD capable CAN Transceivers.
each of which, is connected to a common mode choke, ESD protection as well as a hardware configurable 120-Ohm termination.

..  figure:: can_interface_rev0_2.png
    :width: 600px

    CAN Interface rev. 0.2
    
In rev 0.1 the Termination was implemented to be software-configurable.
This feature has been removed starting from rev 0.2 due to cost and practicality reasons.

..  figure:: can_interface_rev0_1.png
    :width: 600px

    CAN Interface rev. 0.1

Pin-mapping
===========

CAN A
-----
CAN A is directly connected to the spring contact terminal and can be connected to the DB-9 connector with the help of SW1.
lToggling SW1 will disconnect LIN from Pin7 and connect CANA to pin 7 and 2 

.. role:: red

.. list-table::
    :widths: 40 40 80
    :header-rows: 1
   
    *   - Description
        - STM32 Pin
        - Comment
    *   - CAN RX
        - PD0
        - 
    *   - CAN TX
        - PD1
        - 
    *   - CAN STBY
        - PD2
        - 
    *   - Term_EN
        - PD3
        - :red:`Only in rev 0.1`

   
CAN B
-----

CAN B is permanently connected to the CAN B channel of the DB-9 connector in accordance with the Vector pinout.


.. list-table::
    :widths: 40 40 80
    :header-rows: 1
   
    *   - Description
        - STM32 Pin
        - Comment
    *   - CAN RX
        - PB5
        - 
    *   - CAN TX
        - PB6
        - 
    *   - CAN STBY
        - PB7
        - 
    *   - Term_EN
        - PB4
        - :red:`Only in rev 0.1`


LIN
===

LIN is permanently connected to the spring contact terminal and can be connected to the DB-9 connector with the help of SW1.
Toggling SW1 will disconnect CAN-A from Pin 7 & 2 and instead connect LIN to Pin 7.

The User can select to Supply the LIN driver from the mainboard internal 5 V supply, or an external Supply connected to the spring contact terminal.
The LIN supply is specified for up to 24 V and is additionally connected to one of the 0.1” Header connectors.

Using a solid-state Relay The LIN Interface can be software-configured for master- or slave mode.

..  figure:: lin_interface.png
    :width: 600px

    ARDEP LIN INterface

    
Pin-mapping
-----------



.. list-table::
    :widths: 40 40
    :header-rows: 1
   
    *   - Description
        - STM32-Pin
    *   - LIN RX
        - PE1
    *   - LIN TX
        - PE0
    *   - LIN Enable
        - PD7
    *   - LIN Master
        - PB9