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lwIP TCP/IP example on dsPIC33AK512MPS512 using the LAN865x 10BASE-T1S Ethernet MAC-PHY

This example shows how to configure the LAN865x to be used in a 10BASE-T1S Multi-Drop Ethernet network in either PLCA and CSMA/CD mode. It also shows how to r/w registers of the LAN865x during normal operation. Additionally, common Ethernet network functionalities are supported, e.g. ping and iperf.

Building The Application

The parent folder for all the MPLAB X IDE projects for this application is given below:

Application Path : examples\lwIP-dsPIC33AK_Curiosity

To build the application, refer to the table below and open the appropriate project file in MPLABX IDE.

Project Name Description
dsPIC33AK_tc6.X Main project holding the board support package and running the bare metal application. This project pulls in liblwip.X and libtc6.X as libraries.
liblwip.X lwIP TCP/IP stack library
libtc6.X Container to build a library out of the libtc6 source code from the root folder

Hardware setup

Setup

  • Hardware used
  • Hardware setup
    • Connect the PKoB4 USB port on the board to the computer using a USB-C cable.
    • Connect the SPI to 10BASE-T1S interface card to another 10BASE-T1S node (e.g. a second instance of this setup) and optionally a Linux device such as a Raspberry Pi with a EVB-LAN8670 USB device installed and driver loaded.
    • Ensure that end ends of the 10BASE-T1S link are terminated (jumpers installed) and any intermediate device is not terminated (jumpers removed).
    • Build and program one of the dsPIC33AK devices with the default configuration and the second with the node1 configuration. This sets up the first device to act as the 'beacon' on the 10BASE-T1S network (PLCA ID 0) and the second as PLCA ID 1. This also sets the IP addresses for the devices to 192.168.0.100 (first device) and 192.168.0.101 (second device).

Settings for LAN865x

PLCA Configuration is done via #define in the main.c file.

MAC-PHY Settings

The LAN865x MAC-PHY settings are at the beginning of the main.c file:

    #ifndef BOARD_INSTANCE
    #define BOARD_INSTANCE              (0)
    #endif

    #define T1S_PLCA_ENABLE             (true)
    #define T1S_PLCA_NODE_ID            (BOARD_INSTANCE)
    #define T1S_PLCA_NODE_COUNT         (8)
    #define T1S_PLCA_BURST_COUNT        (0)
    #define T1S_PLCA_BURST_TIMER        (0x80)
    #define MAC_PROMISCUOUS_MODE        (false)
    #define MAC_TX_CUT_THROUGH          (true)
    #define MAC_RX_CUT_THROUGH          (false)
    #define DELAY_BEACON_CHECK          (1000)
    #define DELAY_LED                   (333)

The value of BOARD_INSTANCE is set in the default and node1 project configurations, but can be overriden here by defining BOARD_INSTANCE as desired.

PLCA Settings

10BASE-T1S can be used in PLCA or CSMA/CD mode.

  • When using PLCA, the parameters for Local Node ID, Node Count, Max Burst Count and Burst Timer must be configured. These are controlled by the values of the #define settings listed above.
  • The application defaults to using PLCA mode.

Running the Application

  1. Open a Terminal application (e.g. Tera Term) on the computer.
  2. Connect to the COM port and configure the serial settings as follows:
    • Baud: 115200
    • Data: 8 Bits
    • Parity: None
    • Stop: 1 Bit
    • Flow Control: None
  3. Build and program the application using the MPLAB X IDE.
    • Program the first device with the default configuration, and the second with the node1 configuration.
  4. Once both devices are programmed, use the Raspberry Pi (if available) to attempt to ping each device. If a reply is received, the devices are communicating properly on the 10BASE-T1S network.

Application Features

  • Pressing the S1 button will start the UDP iPerf test. This test requires an iPerf server, commonly available in Linux distributions.
  • Pressing the S2 button will enable the Potentiometer test. The Potentiometer test is used with two dsPIC33A Curiosity Platform Development Boards on the 10BASE-T1S network.
    • When enabled on both devices, the potentiometer of one device will be used to control the 3-color LED of the second device, and vice versa. This is done by reading the potentiometer value and sending it in UDP messages between the two devices.
    • This demonstrates a simple usage of remote control of a device across a 10BASE-T1S network.
  • Pressing the S3 button will enable the ping test. The ping test sends ICMP ECHO (ping) messages to the other device (192.168.0.100 -> 192.168.0.101, and vice versa) until the S3 button is pressed again to stop the test. The test reports successful and failed pings and a summary at the end of the test, similarly to the well-known ping operation in most operating systems.