LIN communication with several Slaves using the same software

KaKo_4288106 · ‎Sep 08, 2020

Hi, I am looking for help,

I am currently working on a project that uses LIN for communication, currently there are several slave boards using the same software.

When the Master sends a write I want all the boards to react, but when the Master sends a read request I only want one of the boards to reply, the board to reply will be based on a switch configuration.

Using the Cypress LIN Slave 5.0 module the issue is that I don't have control over the reply, when each of the boards sees the corresponding Frame ID coming in they all attempt to reply to it.

All the boards must use the same software therefore the LIN frames are all set up inside the LIN module, but I was unable to find a way to disable the either the reply or the reply frame itself once the code is running.

I am looking for help, if there is a function that will resolve the problem or a recommendation for a work around.

Regards

Kamil

Len_CONSULTRON · ‎Sep 08, 2020

Kamil,

Method #1.1

Method #1 assumes the HW for each LIN node is in effectively different. This can be accomplished by inserting a unique NAD at manufacturing-time and getting it a part number that infers the NAD difference. To use this style of the method means that on a LIN bus, no two LIN slaves with the same part number (ie. NAD) can be on the bus at the same time. If a node goes down later, the same part number must be used to replace the 'broken' slave.

One way to avoid special NAD programming on the manufacturing line and the unique part number is to add a 'virtual' HW difference for each node.

For example, let's say you install 6 identical Slave nodes on the same LIN bus with the same build HW and SW. It also has the same part number.

A sub-method is to place a 3-switch dip switch on each unit and the system installer needs to select 1 out of 8 combinations of the 3 switches to uniquely address each slave node. This becomes the base of your NAD for each node individual access.

This allows you to replace nodes at will by setting the same 3-switch on the new node to the setting of the old node.

Will this be an acceptable method for your application?

Len

Len
"Engineering is an Art. The Art of Compromise."

View solution in original post

LIN communication with several Slaves using the same software

LIN communication with several Slaves using the same software

Re: LIN communication with several Slaves using the same software