IO611 - LIN Loopback

This example shows how to run a simple loopback using the IO611 I/O module. The IO611 features 2 isolated channels for CAN FD and High-Speed CAN and 2 isolated channels for LIN.

The Simulink model implements a unidirectional LIN loopback transmitting data from channel 2 to channel 1.

This example demonstrates the following modes and features:

Communication between a pair of LIN channels on an IO611 I/O module
Using the Vector Concatenate and several Selector blocks with a LIN Write and LIN Read block
Using the Byte Packing and Byte Unpacking blocks with a LIN Write and LIN Read block
Using the LIN Pack and LIN Unpack blocks with a LIN Write and LIN Read block

Table of Contents

Setup Prerequisites Connection Diagram Initialize and Open the Simulink Model Model Description Sending LIN Data from Channel 1 to Channel 2 Build, Download, and Run the Example Results Ch1RxMaster_Ch2TxSlave Additional References

Setup

Prerequisites

You will require the following to run this example:

Speedgoat real-time target machine with one IO611 I/O module installed
1x LIN loopback cable according to the IO611 Pin Mapping
1x external power supply capable of outputting 8-18 V

Connection Diagram

For this example, connect LIN channel 1 and channel 2 in a loopback configuration. Refer to the diagram below for the necessary pin wiring. Additionally an external power supply is required to power the LIN Bus with a voltage between 8 V and 18 V.

Initialize and Open the Simulink Model

 
% Open Simulink model
modelName = 'sgMdl_IO611_LIN_Loopback';
open_system(modelName);

Model Description

The Simulink model contains one subsystems that represent the LIN communication. This subsystem is used to send LIN messages from channel 1 to channel 2.

The LIN communication is controlled by the LIN Read blocks configured as Master. The Master on channel 1 sends out a header requesting a response from a Slave on channel 2 with a matching ID. All LIN Read blocks are placed inside a triggered subsystem which executes the blocks alternately. This to schedule the communication on the LIN Bus in order to avoid conflicting header requests.

Sending LIN Data from Channel 1 to Channel 2

 
% open Ch1RxMaster_Ch2TxSlave subsystem
speedgoat.model.highlight([modelName '/Ch1RxMaster_Ch2TxSlave'],'Open',true);

In this subsystem, on the left-hand side, each of the eight signals are prepared differently to be sent as a LIN message. The first option utilizes the Vector Concatenate block to combine multiple uint8 signals into an 8-byte uint8 vector. The second option utilizes the Byte Packing block to combine multiple uint8 signals into an 8-byte uint8 vector. The third option utilizes the LIN Pack block to load and parse a .ldf file. This file describes a set of uint8 signals to be packed into a LIN frame and output as an 8-byte uint8 vector. All of these vectors are wired to a LIN Write block with LIN message IDs 48, 49 and 50.

On the right-hand side, the expected LIN message IDs are specified separately in two LIN Read block masks. Consequently, the two IDs are available as outputs on the respective block mask. The division of the 8-byte LIN messages into signals is again done differently for each message. The first option utilizes the Selector block to index which uint8 to grab from the vector. The second option utilizes the Byte Unpacking block to map the signals to an output. The third option utilizes the LIN Unpack block to parse the same .ldf file again to unpack the LIN frame to output single signals again.

Build, Download, and Run the Example

To run the example, either run the following code section or click the Run on Target button in the REAL-TIME tab in the Simulink model.

 
% Select and load the .ldf file for the LIN Pack and Unpack blocks
set_param([modelName, '/Ch1RxMaster_Ch2TxSlave/LIN Pack'], 'LDFFileName', 'LINDescriptorFile.ldf', 'selectedFrameName', 'Frame_06');
set_param([modelName, '/Ch1RxMaster_Ch2TxSlave/Enabled Subsystem2/LIN Unpack'], 'LDFFileName', 'LINDescriptorFile.ldf', 'selectedFrameName', 'Frame_06');
 
% Build the Simulink model
slbuild(modelName);         % this will create the real-time application file (.mldatx)
 
% Create and connect to the Speedgoat real-time target machine
tg = slrealtime;            
tg.connect;
 
% Download the real-time application to the target machine and set stop time
tg.load(modelName);
tg.setStopTime(10);
 
% Connect the Simulink model with external mode to the real-time application on the target machine
set_param(modelName,'SimulationMode',   'external')   % put model into External Mode
set_param(modelName,'SimulationCommand','connect')    % connect with External Mode   
set_param(modelName,'SimulationCommand','start')      % start real-time application through Simulink toolstrip
 
% Wait until the real-time application reaches the stop time of 10 seconds