SSP offset feature test

Implement feature test for secondary sampling point user defined offset. All options of SW offset, measured offset, SW + measured offset must be executed.

This needs Data and Secondary sampling points in Status Bus: #260 (closed)

assigned to @furavikt

Test proposal is further described in #260 (closed)

Hi, I added 3 sample signals to Status Bus in: #260 (closed)

These are:

1. Sample trigger for Nominal Bit Time delayed by 1 clock cycle.
2. Sample trigger for Data Bit Time delayed by 1 clock cycle.
3. Sample trigger for Secondary Sample delayed by 1 clock cycle.

Little Design description: If Core is transmitter, it is using Nominal Sampling point up to Bit-rate switch in EDL(FDF) bit. After the switch, it will start using Data-Sample. Secondary sample point is invisible to CAN Core (it is used only in Bus sampling module. CAN Core is still processing receive data with Data Sample. To make sure that correct data are processed (since RX data might not be yet there due to roundtrip), data into bit-destuffing are driven from post bit stuffing data.

This-way, Protocol Control receives what it transmitted in the Same bit. Note that this does not mind since after bit-rate switch Core is the only transmitter.

Now to the error handling. If the Core which is transmitting in Data-Bit rate is automatically receiving what it transmitted, then it has no way of knowing what has happened on the bus (what errors are there). But what types of Errors does transmitter in Data-Phase needs to detect? It will detect Bit-errors in Bus Sampling via secondary sample point. It should detect, Stuff errors if some other unit starts transmitting Error Frame. But if this happends, the unit will anyway detect Bit-Error sooner or later (due to stuff bit). To sum it up: Transmitter in Data phase needs to only detect bit errors and it will even recognize error frame by bit error detection mechanism.

Now to the test: I would propose to wait for a Bit-rate switch (sp_control signal is also available in Status Bus), and then measure number of clock cycles it takes for first occurence of Secondary Sample Point.

created branch 205-ssp-offset-feature-test to address this issue

added Release 2.3 label

mentioned in merge request !306 (merged)

closed via merge request !306 (merged)

mentioned in commit 72ab7315

reopened

mentioned in merge request !311 (merged)

closed via merge request !311 (merged)

mentioned in commit 08960454

reopened

mentioned in merge request !312 (merged)

closed via merge request !312 (merged)

mentioned in commit 381d95c6

reopened

mentioned in merge request !313 (merged)

closed via merge request !313 (merged)